From 41c24a23fd561abafc54f7f9ccacdd483656da8c Mon Sep 17 00:00:00 2001
From: Rene Schmidt <rene@sdo.sh>
Date: Tue, 25 Jun 2024 22:32:40 +0200
Subject: [PATCH] chore: fixed many issues

---
 composer.json                                |   3 +-
 phpstan-baseline.neon                        |  10 -
 phpstan.neon                                 |   2 +-
 rector.php                                   |  58 +++++
 src/Http/Client.php                          |   6 -
 src/Resource/Account.php                     |  18 +-
 src/Resource/Auth.php                        |   2 +-
 src/Resource/Avatar.php                      |   3 +-
 src/Resource/Directory.php                   |  49 ++--
 src/Resource/File.php                        | 173 ++++++-------
 src/Resource/Group.php                       |   2 +-
 src/Resource/Library.php                     |  18 +-
 src/Resource/Multi.php                       |  37 ++-
 src/Resource/Resource.php                    |  18 +-
 src/Resource/ShareLinks.php                  |  18 +-
 src/Resource/StarredFile.php                 |  31 +--
 src/Type/Account.php                         |  47 ++--
 src/Type/Avatar.php                          |   6 +-
 src/Type/DirectoryItem.php                   |  22 +-
 src/Type/FileHistoryItem.php                 |   4 +-
 src/Type/Group.php                           |  12 +-
 src/Type/SharedLink.php                      |  18 +-
 src/Type/SharedLinkPermissions.php           |   5 +-
 src/Type/Type.php                            |  11 +-
 src/Type/TypeInterface.php                   |   5 -
 test/bootstrap.php                           |   6 +-
 test/functional/FunctionalTestCase.php       |  24 +-
 test/functional/Resource/AccountTest.php     |  34 +--
 test/functional/Resource/FileTest.php        |  71 +++---
 test/functional/Resource/GroupTest.php       |  13 +-
 test/functional/Resource/ShareLinksTest.php  |  32 +--
 test/functional/Resource/StarredFileTest.php |  39 ++-
 test/unit/Http/ClientUnitTest.php            |   8 +-
 test/unit/Resource/AccountTest.php           |  50 ++--
 test/unit/Resource/AvatarTest.php            |  24 +-
 test/unit/Resource/DirectoryTest.php         | 125 ++++-----
 test/unit/Resource/FileTest.php              | 254 ++++++++-----------
 test/unit/Resource/GroupTest.php             |   3 +-
 test/unit/Resource/LibraryTest.php           |  59 ++---
 test/unit/Resource/MultiTest.php             |  40 ++-
 test/unit/Resource/ResourceTest.php          |  16 +-
 test/unit/Resource/ShareLinksTest.php        |  48 ++--
 test/unit/Resource/StarredFileTest.php       |  90 +++----
 test/unit/Stubs/FileResourceStub.php         |  18 +-
 test/unit/Type/DirectoryItemUnitTest.php     |  13 +-
 test/unit/Type/TypeUnitTest.php              |  68 ++---
 test/unit/UnitTestCase.php                   |   8 +-
 47 files changed, 713 insertions(+), 908 deletions(-)
 create mode 100644 rector.php

diff --git a/composer.json b/composer.json
index 39d743d..0206933 100644
--- a/composer.json
+++ b/composer.json
@@ -33,7 +33,8 @@
     "squizlabs/php_codesniffer": "~3.7",
     "phpunit/php-timer": "~5.0",
     "fzaninotto/faker": "~1.5",
-    "phpstan/phpstan": "^1.11"
+    "phpstan/phpstan": "^1.11",
+    "rector/rector": "^1.1"
   },
   "type": "library",
   "autoload": {
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 6fcfd50..59114f6 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -35,11 +35,6 @@ parameters:
 			count: 1
 			path: src/Resource/File.php
 
-		-
-			message: "#^Parameter \\#2 \\$uri of method GuzzleHttp\\\\Client\\:\\:request\\(\\) expects Psr\\\\Http\\\\Message\\\\UriInterface\\|string, array\\<string\\>\\|string given\\.$#"
-			count: 1
-			path: src/Resource/File.php
-
 		-
 			message: "#^Method Seafile\\\\Client\\\\Resource\\\\Library\\:\\:decrypt\\(\\) has parameter \\$options with no value type specified in iterable type array\\.$#"
 			count: 1
@@ -70,11 +65,6 @@ parameters:
 			count: 1
 			path: src/Resource/Multi.php
 
-		-
-			message: "#^PHPDoc tag @return with type mixed is not subtype of native type string\\.$#"
-			count: 1
-			path: src/Resource/Resource.php
-
 		-
 			message: "#^PHPDoc tag @return with type mixed is not subtype of native type string\\.$#"
 			count: 1
diff --git a/phpstan.neon b/phpstan.neon
index d11daea..5f99112 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -2,4 +2,4 @@ includes:
 	- phpstan-baseline.neon
 
 parameters:
-	level: 7
\ No newline at end of file
+	level: 7
diff --git a/rector.php b/rector.php
new file mode 100644
index 0000000..5c04965
--- /dev/null
+++ b/rector.php
@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\Carbon\Rector\FuncCall\DateFuncCallToCarbonRector;
+use Rector\CodingStyle\Rector\FuncCall\CountArrayToEmptyArrayComparisonRector;
+use Rector\CodingStyle\Rector\String_\SymplifyQuoteEscapeRector;
+use Rector\Config\RectorConfig;
+use Rector\Doctrine\Set\DoctrineSetList;
+use Rector\Naming\Rector\Assign\RenameVariableToMatchMethodCallReturnTypeRector;
+use Rector\Php54\Rector\Array_\LongArrayToShortArrayRector;
+use Rector\Php70\Rector\FunctionLike\ExceptionHandlerTypehintRector;
+use Rector\Set\ValueObject\LevelSetList;
+use Rector\Set\ValueObject\SetList;
+use Rector\Symfony\Set\FOSRestSetList;
+use Rector\Symfony\Set\SensiolabsSetList;
+use Rector\Symfony\Set\SymfonySetList;
+use Rector\ValueObject\PhpVersion;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->paths([
+        __DIR__ . '/src',
+        __DIR__ . '/test',
+    ]);
+
+    $rectorConfig->phpVersion(PhpVersion::PHP_82);
+
+    $rectorConfig->sets([
+        LevelSetList::UP_TO_PHP_82,
+        SetList::CODE_QUALITY,
+        SetList::CODING_STYLE,
+        SetList::DEAD_CODE,
+        SetList::NAMING,
+        SetList::PRIVATIZATION,
+        SetList::STRICT_BOOLEANS,
+        DoctrineSetList::ANNOTATIONS_TO_ATTRIBUTES,
+        FOSRestSetList::ANNOTATIONS_TO_ATTRIBUTES,
+        SensiolabsSetList::ANNOTATIONS_TO_ATTRIBUTES,
+        SymfonySetList::ANNOTATIONS_TO_ATTRIBUTES,
+        SetList::TYPE_DECLARATION, // https://getrector.com/blog/new-in-rector-015-complete-safe-and-known-type-declarations
+    ]);
+
+    $rectorConfig->rules([
+        CountArrayToEmptyArrayComparisonRector::class,
+        DateFuncCallToCarbonRector::class,
+        LongArrayToShortArrayRector::class,
+        RenameVariableToMatchMethodCallReturnTypeRector::class,
+        SymplifyQuoteEscapeRector::class,
+        ExceptionHandlerTypehintRector::class
+    ]);
+
+    $rectorConfig->importNames();
+    $rectorConfig->autoloadPaths([
+        __DIR__ . '/vendor/autoload.php',
+    ]);
+
+    $rectorConfig->parallel();
+};
diff --git a/src/Http/Client.php b/src/Http/Client.php
index d2db6bc..bb2c967 100644
--- a/src/Http/Client.php
+++ b/src/Http/Client.php
@@ -43,8 +43,6 @@ public function __construct(array $config = [])
 
     /**
      * @param string|UriInterface $uri URI for request
-     * @param array $options
-     * @return ResponseInterface
      * @throws GuzzleException
      */
     public function get($uri, array $options = []): ResponseInterface
@@ -54,8 +52,6 @@ public function get($uri, array $options = []): ResponseInterface
 
     /**
      * @param string|UriInterface $uri URI for request
-     * @param array $options
-     * @return ResponseInterface
      * @throws GuzzleException
      */
     public function put($uri, array $options = []): ResponseInterface
@@ -65,8 +61,6 @@ public function put($uri, array $options = []): ResponseInterface
 
     /**
      * @param string|UriInterface $uri URI for request
-     * @param array $options
-     * @return ResponseInterface
      * @throws GuzzleException
      */
     public function delete($uri, array $options = []): ResponseInterface
diff --git a/src/Resource/Account.php b/src/Resource/Account.php
index 1a75487..688e3b8 100644
--- a/src/Resource/Account.php
+++ b/src/Resource/Account.php
@@ -3,6 +3,7 @@
 namespace Seafile\Client\Resource;
 
 use Exception;
+use GuzzleHttp\Exception\GuzzleException;
 use Seafile\Client\Type\Type;
 use \Seafile\Client\Type\Account as AccountType;
 use Seafile\Client\Type\TypeInterface;
@@ -18,7 +19,7 @@
  */
 class Account extends Resource
 {
-    const API_VERSION = '2';
+    public const API_VERSION = '2';
 
     /**
      * List accounts
@@ -27,6 +28,7 @@ class Account extends Resource
      *
      * @return AccountType[]
      * @throws Exception
+     * @throws GuzzleException
      */
     public function getAll(): array
     {
@@ -50,8 +52,8 @@ public function getAll(): array
      *
      * @param string $emailAddress Email address
      *
-     * @return AccountType
      * @throws Exception
+     * @throws GuzzleException
      */
     public function getByEmail(string $emailAddress): AccountType
     {
@@ -71,8 +73,8 @@ public function getByEmail(string $emailAddress): AccountType
      *
      * @param string $emailAddress Email address to get info of
      *
-     * @return AccountType|TypeInterface
      * @throws Exception
+     * @throws GuzzleException
      */
     public function getInfo(string $emailAddress): TypeInterface
     {
@@ -93,8 +95,8 @@ public function getInfo(string $emailAddress): TypeInterface
      *
      * @param AccountType $accountType AccountType instance with data for new account
      *
-     * @return bool
      * @throws Exception
+     * @throws GuzzleException
      */
     public function create(AccountType $accountType): bool
     {
@@ -128,7 +130,6 @@ public function create(AccountType $accountType): bool
      *
      * @param AccountType $accountType AccountType instance with updated data
      *
-     * @return bool
      * @throws Exception
      */
     public function update(AccountType $accountType): bool
@@ -212,8 +213,8 @@ public function update(AccountType $accountType): bool
      *
      * @param string $email Email address
      *
-     * @return bool
      * @throws Exception
+     * @throws GuzzleException
      */
     public function removeByEmail(string $email): bool
     {
@@ -226,12 +227,11 @@ public function removeByEmail(string $email): bool
      * Requires admin permissions
      *
      * @param AccountType $accountType Account to remove
-     *
-     * @return bool
+     * @throws GuzzleException
      */
     public function remove(AccountType $accountType): bool
     {
-        if (empty($accountType->email)) {
+        if ($accountType->email === null || $accountType->email === '' || $accountType->email === '0') {
             return false;
         }
 
diff --git a/src/Resource/Auth.php b/src/Resource/Auth.php
index 3dec459..41b3505 100644
--- a/src/Resource/Auth.php
+++ b/src/Resource/Auth.php
@@ -13,5 +13,5 @@
  */
 class Auth extends Resource implements ResourceInterface
 {
-    const API_VERSION = '2';
+    public const API_VERSION = '2';
 }
diff --git a/src/Resource/Avatar.php b/src/Resource/Avatar.php
index 6ac7150..bedf2de 100644
--- a/src/Resource/Avatar.php
+++ b/src/Resource/Avatar.php
@@ -72,7 +72,7 @@ public function getGroupAvatar(GroupType $groupType, int $size = 80)
      */
     protected function getAvatar(Type $type, int $size)
     {
-        if (!is_int($size) || $size < 1) {
+        if ($size < 1) {
             throw new Exception('Illegal avatar size');
         }
 
@@ -104,7 +104,6 @@ protected function getAvatar(Type $type, int $size)
      *
      * @param AccountType $accountType AccountType instance with data for new account
      *
-     * @return bool
      * @throws Exception
      */
     public function createUserAvatar(AccountType $accountType): bool
diff --git a/src/Resource/Directory.php b/src/Resource/Directory.php
index a15afa9..95d7ddc 100644
--- a/src/Resource/Directory.php
+++ b/src/Resource/Directory.php
@@ -18,25 +18,25 @@
  */
 class Directory extends Resource
 {
-    const API_VERSION = '2';
+    public const API_VERSION = '2';
 
     /**
      * Get all items of a directory in a library
      *
-     * @param LibraryType $library Library type
+     * @param LibraryType $libraryType Library type
      * @param string $dir Directory path
      *
      * @return DirectoryItem[]
      * @throws Exception
      * @throws GuzzleException
      */
-    public function getAll(LibraryType $library, string $dir = '/')
+    public function getAll(LibraryType $libraryType, string $dir = '/'): array
     {
         $clippedBaseUri = $this->clipUri($this->getApiBaseUrl());
 
         $response = $this->client->request(
             'GET',
-            $clippedBaseUri . '/repos/' . $library->id . '/dir/',
+            $clippedBaseUri . '/repos/' . $libraryType->id . '/dir/',
             [
                 'query' => ['p' => $dir],
             ]
@@ -63,17 +63,16 @@ public function getAll(LibraryType $library, string $dir = '/')
     /**
      * Check if $dirName exists within $parentDir
      *
-     * @param LibraryType $library Library instance
+     * @param LibraryType $libraryType Library instance
      * @param string $dirItemName DirectoryItem name
      * @param string $parentDir Parent directory
      *
-     * @return bool
      * @throws Exception
      * @throws GuzzleException
      */
-    public function exists(LibraryType $library, string $dirItemName, string $parentDir = '/')
+    public function exists(LibraryType $libraryType, string $dirItemName, string $parentDir = '/'): bool
     {
-        $directoryItems = $this->getAll($library, $parentDir);
+        $directoryItems = $this->getAll($libraryType, $parentDir);
 
         foreach ($directoryItems as $directoryItem) {
             if ($directoryItem->name === $dirItemName) {
@@ -87,7 +86,7 @@ public function exists(LibraryType $library, string $dirItemName, string $parent
     /**
      * Create directory within $parentDir
      *
-     * @param LibraryType $library Library instance
+     * @param LibraryType $libraryType Library instance
      * @param string $dirName Directory name
      * @param string $parentDir Parent directory
      * @param bool $recursive Recursive create
@@ -96,7 +95,7 @@ public function exists(LibraryType $library, string $dirItemName, string $parent
      * @throws Exception
      * @throws GuzzleException
      */
-    public function create(LibraryType $library, string $dirName, string $parentDir = '/', bool $recursive = false)
+    public function create(LibraryType $libraryType, string $dirName, string $parentDir = '/', bool $recursive = false)
     {
         if ($recursive) {
             $response = false;
@@ -107,8 +106,8 @@ public function create(LibraryType $library, string $dirName, string $parentDir
                 $parentPath = '/' . implode('/', $tmp);
                 $tmp[] = $part;
 
-                if ($this->exists($library, $part, $parentPath) === false) {
-                    $response = $this->create($library, $part, $parentPath, false);
+                if ($this->exists($libraryType, $part, $parentPath) === false) {
+                    $response = $this->create($libraryType, $part, $parentPath, false);
                 }
             }
 
@@ -116,19 +115,19 @@ public function create(LibraryType $library, string $dirName, string $parentDir
         }
 
         // only create folder which is not empty to prevent wrong implementation
-        if (empty($dirName)) {
+        if ($dirName === '' || $dirName === '0') {
             return false;
         }
 
         // Do not create folders that already exist
-        if ($this->exists($library, $dirName, $parentDir)) {
+        if ($this->exists($libraryType, $dirName, $parentDir)) {
             return false;
         }
 
         $uri = sprintf(
             '%s/repos/%s/dir/?p=%s/%s',
             $this->clipUri($this->getApiBaseUrl()),
-            $library->id,
+            $libraryType->id,
             rtrim($parentDir, '/'),
             $dirName
         );
@@ -153,22 +152,20 @@ public function create(LibraryType $library, string $dirName, string $parentDir
     /**
      * Remove a directory
      *
-     * @param LibraryType $library Library instance
+     * @param LibraryType $libraryType Library instance
      * @param string $directoryPath Directory path
-     *
-     * @return bool
      */
-    public function remove(LibraryType $library, string $directoryPath)
+    public function remove(LibraryType $libraryType, string $directoryPath): bool
     {
         // don't allow empty paths
-        if (empty($directoryPath)) {
+        if ($directoryPath === '' || $directoryPath === '0') {
             return false;
         }
 
         $uri = sprintf(
             '%s/repos/%s/dir/?p=%s',
             $this->clipUri($this->getApiBaseUrl()),
-            $library->id,
+            $libraryType->id,
             rtrim($directoryPath, '/')
         );
 
@@ -186,23 +183,21 @@ public function remove(LibraryType $library, string $directoryPath)
     /**
      * Rename a directory
      *
-     * @param LibraryType $library Library object
+     * @param LibraryType $libraryType Library object
      * @param string $directoryPath Directory path
      * @param string $newDirectoryName New directory name
-     *
-     * @return bool
      */
-    public function rename(LibraryType $library, string $directoryPath, string $newDirectoryName)
+    public function rename(LibraryType $libraryType, string $directoryPath, string $newDirectoryName): bool
     {
         // don't allow empty paths
-        if (empty($directoryPath) || empty($newDirectoryName)) {
+        if ($directoryPath === '' || $directoryPath === '0' || ($newDirectoryName === '' || $newDirectoryName === '0')) {
             return false;
         }
 
         $uri = sprintf(
             '%s/repos/%s/dir/?p=%s',
             $this->clipUri($this->getApiBaseUrl()),
-            $library->id,
+            $libraryType->id,
             rtrim($directoryPath, '/')
         );
 
diff --git a/src/Resource/File.php b/src/Resource/File.php
index 50b793f..04b56c2 100644
--- a/src/Resource/File.php
+++ b/src/Resource/File.php
@@ -4,8 +4,6 @@
 
 use Exception;
 use GuzzleHttp\Exception\GuzzleException;
-use GuzzleHttp\Psr7\Response;
-use http\Env\Request;
 use InvalidArgumentException;
 use Psr\Http\Message\ResponseInterface;
 use Seafile\Client\Type\DirectoryItem;
@@ -23,77 +21,73 @@
  */
 class File extends Resource
 {
-    const API_VERSION = '2';
+    public const API_VERSION = '2';
 
     /**
      * Mode of operation: copy
      */
-    const OPERATION_COPY = 1;
+    public const OPERATION_COPY = 1;
 
     /**
      * Mode of operation: move
      */
-    const OPERATION_MOVE = 2;
+    public const OPERATION_MOVE = 2;
 
     /**
      * Mode of operation: create
      */
-    const OPERATION_CREATE = 3;
+    public const OPERATION_CREATE = 3;
 
     /**
      * Get download URL of a file
      *
-     * @param LibraryType $library Library instance
-     * @param DirectoryItem $item Item instance
+     * @param LibraryType $libraryType Library instance
+     * @param DirectoryItem $directoryItem Item instance
      * @param string $dir Dir string
      * @param int $reuse Reuse more than once per hour
      *
-     * @return string
      * @throws GuzzleException
      */
-    public function getDownloadUrl(LibraryType $library, DirectoryItem $item, string $dir = '/', int $reuse = 1)
+    public function getDownloadUrl(LibraryType $libraryType, DirectoryItem $directoryItem, string $dir = '/', int $reuse = 1): ?string
     {
         $url = $this->getApiBaseUrl()
             . '/repos/'
-            . $library->id
+            . $libraryType->id
             . '/file/'
             . '?reuse=' . $reuse
-            . '&p=' . $this->urlEncodePath($dir . $item->name);
+            . '&p=' . $this->urlEncodePath($dir . $directoryItem->name);
 
         $response = $this->client->request('GET', $url);
         $downloadUrl = (string)$response->getBody();
 
-        return preg_replace("/\"/", '', $downloadUrl);
+        return preg_replace('/"/', '', $downloadUrl);
     }
 
     /**
      * URL-encode path string
      *
      * @param string $path Path string
-     *
-     * @return string
      */
-    protected function urlEncodePath(string $path)
+    protected function urlEncodePath(string $path): string
     {
-        return implode('/', array_map('rawurlencode', explode('/', (string)$path)));
+        return implode('/', array_map('rawurlencode', explode('/', $path)));
     }
 
     /**
      * Get download URL of a file from a Directory item
      *
-     * @param LibraryType $library Library instance
-     * @param DirectoryItem $item Item instance
+     * @param LibraryType $libraryType Library instance
+     * @param DirectoryItem $directoryItem Item instance
      * @param string $localFilePath Save file to path
      * @param string $dir Dir string
      * @param int $reuse Reuse more than once per hour
      *
-     * @return ResponseInterface
      * @throws Exception
      * @throws GuzzleException
      */
     public function downloadFromDir(
-        LibraryType   $library,
-        DirectoryItem $item,
+        LibraryType   $libraryType,
+        DirectoryItem $directoryItem,
         string        $localFilePath,
         string        $dir,
         int           $reuse = 1
@@ -103,7 +97,7 @@ public function downloadFromDir(
             throw new Exception('File already exists');
         }
 
-        $downloadUrl = $this->getDownloadUrl($library, $item, $dir, $reuse);
+        $downloadUrl = $this->getDownloadUrl($libraryType, $directoryItem, $dir, $reuse);
 
         return $this->client->request('GET', $downloadUrl, ['save_to' => $localFilePath]);
     }
@@ -111,64 +105,62 @@ public function downloadFromDir(
     /**
      * Get download URL of a file
      *
-     * @param LibraryType $library Library instance
+     * @param LibraryType $libraryType Library instance
      * @param string $filePath Save file to path
      * @param string $localFilePath Local file path
      * @param int $reuse Reuse more than once per hour
      *
-     * @return ResponseInterface
      * @throws Exception
      * @throws GuzzleException
      */
-    public function download(LibraryType $library, string $filePath, string $localFilePath, int $reuse = 1)
+    public function download(LibraryType $libraryType, string $filePath, string $localFilePath, int $reuse = 1): ResponseInterface
     {
-        $item = new DirectoryItem();
-        $item->name = basename($filePath);
+        $directoryItem = new DirectoryItem();
+        $directoryItem->name = basename($filePath);
 
         $dir = str_replace("\\", "/", dirname($filePath)); // compatibility for windows
 
-        return $this->downloadFromDir($library, $item, $localFilePath, $dir, $reuse);
+        return $this->downloadFromDir($libraryType, $directoryItem, $localFilePath, $dir, $reuse);
     }
 
     /**
      * Update file
      *
-     * @param LibraryType $library Library instance
+     * @param LibraryType $libraryType Library instance
      * @param string $localFilePath Local file path
      * @param string $dir Library dir
      * @param mixed $filename File name, or false to use the name from $localFilePath
      *
-     * @return ResponseInterface
      * @throws Exception
      * @throws GuzzleException
      */
-    public function update(LibraryType $library, string $localFilePath, string $dir = '/', $filename = false): ResponseInterface
+    public function update(LibraryType $libraryType, string $localFilePath, string $dir = '/', mixed $filename = false): ResponseInterface
     {
-        return $this->upload($library, $localFilePath, $dir, $filename, false);
+        return $this->upload($libraryType, $localFilePath, $dir, $filename, false);
     }
 
     /**
      * Get upload URL
      *
-     * @param LibraryType $library Library instance
+     * @param LibraryType $libraryType Library instance
      * @param bool $newFile Is new file (=upload) or not (=update)
      * @param string $dir Directory to upload to
      *
      * @return String Upload link
      * @throws GuzzleException
      */
-    public function getUploadUrl(LibraryType $library, bool $newFile = true, string $dir = "/"): string
+    public function getUploadUrl(LibraryType $libraryType, bool $newFile = true, string $dir = "/"): string
     {
         $url = $this->getApiBaseUrl()
             . '/repos/'
-            . $library->id
+            . $libraryType->id
             . '/' . ($newFile ? 'upload' : 'update') . '-link/'
             . '?p=' . $dir;
 
         $response = $this->client->request('GET', $url);
         $uploadLink = (string)$response->getBody();
 
-        return preg_replace("/\"/", '', $uploadLink);
+        return preg_replace('/"/', '', $uploadLink);
     }
 
     /**
@@ -178,21 +170,15 @@ public function getUploadUrl(LibraryType $library, bool $newFile = true, string
      * @param string $dir Library dir
      * @param bool $newFile Is new file (=upload) or not (=update)
      * @param mixed $newFilename New file name, or false to use the name from $localFilePath
-     *
-     * @return array
      */
     public function getMultiPartParams(
         string $localFilePath,
         string $dir,
         bool   $newFile = true,
-               $newFilename = false
+               mixed $newFilename = false
     ): array
     {
-        if ($newFilename === false) {
-            $fileBaseName = basename($localFilePath);
-        } else {
-            $fileBaseName = $newFilename;
-        }
+        $fileBaseName = $newFilename === false ? basename($localFilePath) : $newFilename;
 
         $multiPartParams = [
             [
@@ -228,21 +214,20 @@ public function getMultiPartParams(
     /**
      * Upload file
      *
-     * @param LibraryType $library Library instance
+     * @param LibraryType $libraryType Library instance
      * @param string $localFilePath Local file path
      * @param string $dir Library dir
      * @param mixed $newFilename New file name, or false to use the name from $localFilePath
      * @param bool $newFile Is new file (=upload) or not (=update)
      *
-     * @return ResponseInterface
      * @throws Exception
      * @throws GuzzleException
      */
     public function upload(
-        LibraryType $library,
+        LibraryType $libraryType,
         string      $localFilePath,
         string      $dir = '/',
-                    $newFilename = false,
+                    mixed $newFilename = false,
         bool        $newFile = true
     ): ResponseInterface
     {
@@ -252,7 +237,7 @@ public function upload(
 
         return $this->client->request(
             'POST',
-            $this->getUploadUrl($library, $newFile, $dir),
+            $this->getUploadUrl($libraryType, $newFile, $dir),
             [
                 'headers' => ['Accept' => '*/*'],
                 'multipart' => $this->getMultiPartParams($localFilePath, $dir, $newFile, $newFilename),
@@ -263,18 +248,17 @@ public function upload(
     /**
      * Get file detail
      *
-     * @param LibraryType $library Library instance
+     * @param LibraryType $libraryType Library instance
      * @param string $remoteFilePath Remote file path
      *
-     * @return DirectoryItem
      * @throws GuzzleException
      * @throws Exception
      */
-    public function getFileDetail(LibraryType $library, string $remoteFilePath): DirectoryItem
+    public function getFileDetail(LibraryType $libraryType, string $remoteFilePath): DirectoryItem
     {
         $url = $this->getApiBaseUrl()
             . '/repos/'
-            . $library->id
+            . $libraryType->id
             . '/file/detail/'
             . '?p=' . $this->urlEncodePath($remoteFilePath);
 
@@ -288,23 +272,22 @@ public function getFileDetail(LibraryType $library, string $remoteFilePath): Dir
     /**
      * Remove a file
      *
-     * @param LibraryType $library Library object
+     * @param LibraryType $libraryType Library object
      * @param string $filePath File path
      *
-     * @return bool
      * @throws GuzzleException
      */
-    public function remove(LibraryType $library, string $filePath): bool
+    public function remove(LibraryType $libraryType, string $filePath): bool
     {
         // do not allow empty paths
-        if (empty($filePath)) {
+        if ($filePath === '' || $filePath === '0') {
             return false;
         }
 
         $uri = sprintf(
             '%s/repos/%s/file/?p=%s',
             $this->clipUri($this->getApiBaseUrl()),
-            $library->id,
+            $libraryType->id,
             $this->urlEncodePath($filePath)
         );
 
@@ -322,29 +305,28 @@ public function remove(LibraryType $library, string $filePath): bool
     /**
      * Rename a file
      *
-     * @param LibraryType $library Library object
-     * @param DirectoryItem $dirItem Directory item to rename
+     * @param LibraryType $libraryType Library object
+     * @param DirectoryItem $directoryItem Directory item to rename
      * @param string $newFilename New file name; see "Issues" in the readme
      *
-     * @return bool
      * @throws GuzzleException
      */
-    public function rename(LibraryType $library, DirectoryItem $dirItem, string $newFilename): bool
+    public function rename(LibraryType $libraryType, DirectoryItem $directoryItem, string $newFilename): bool
     {
-        $filePath = $dirItem->dir . $dirItem->name;
+        $filePath = $directoryItem->dir . $directoryItem->name;
 
-        if (empty($filePath)) {
+        if ($filePath === '' || $filePath === '0') {
             throw new InvalidArgumentException('Invalid file path: must not be empty');
         }
 
-        if (empty($newFilename) || strpos($newFilename, '/') === 0) {
+        if ($newFilename === '' || $newFilename === '0' || str_starts_with($newFilename, '/')) {
             throw new InvalidArgumentException('Invalid new file name: length must be >0 and must not start with /');
         }
 
         $uri = sprintf(
             '%s/repos/%s/file/?p=%s',
             $this->clipUri($this->getApiBaseUrl()),
-            $library->id,
+            $libraryType->id,
             $this->urlEncodePath($filePath)
         );
 
@@ -369,7 +351,7 @@ public function rename(LibraryType $library, DirectoryItem $dirItem, string $new
         $success = $response->getStatusCode() === 200;
 
         if ($success) {
-            $dirItem->name = $newFilename;
+            $directoryItem->name = $newFilename;
         }
 
         return $success;
@@ -384,7 +366,6 @@ public function rename(LibraryType $library, DirectoryItem $dirItem, string $new
      * @param string $dstDirectoryPath Destination directory path
      * @param int $operation Operation mode
      *
-     * @return bool
      * @throws GuzzleException
      */
     public function copy(
@@ -396,7 +377,7 @@ public function copy(
     ): bool
     {
         // do not allow empty paths
-        if (empty($srcFilePath) || empty($dstDirectoryPath)) {
+        if ($srcFilePath === '' || $srcFilePath === '0' || ($dstDirectoryPath === '' || $dstDirectoryPath === '0')) {
             return false;
         }
 
@@ -448,7 +429,6 @@ public function copy(
      * @param LibraryType $dstLibrary Destination library object
      * @param string $dstDirectoryPath Destination directory path
      *
-     * @return bool
      * @throws GuzzleException
      */
     public function move(
@@ -464,50 +444,48 @@ public function move(
     /**
      * Get file revision download URL
      *
-     * @param LibraryType $library Source library object
-     * @param DirectoryItem $dirItem Item instance
+     * @param LibraryType $libraryType Source library object
+     * @param DirectoryItem $directoryItem Item instance
      * @param FileHistoryItem $fileHistoryItem FileHistory item instance
      *
-     * @return string|string[]
      * @throws GuzzleException
      */
     public function getFileRevisionDownloadUrl(
-        LibraryType     $library,
-        DirectoryItem   $dirItem,
+        LibraryType     $libraryType,
+        DirectoryItem   $directoryItem,
         FileHistoryItem $fileHistoryItem
-    )
+    ): ?string
     {
         $url = $this->getApiBaseUrl()
             . '/repos/'
-            . $library->id
+            . $libraryType->id
             . '/file/revision/'
-            . '?p=' . $this->urlEncodePath($dirItem->path . $dirItem->name)
+            . '?p=' . $this->urlEncodePath($directoryItem->path . $directoryItem->name)
             . '&commit_id=' . $fileHistoryItem->id;
 
         $response = $this->client->request('GET', $url);
 
-        return preg_replace("/\"/", '', (string)$response->getBody());
+        return preg_replace('/"/', '', (string)$response->getBody());
     }
 
     /**
      * Download file revision
      *
-     * @param LibraryType $library Source library object
-     * @param DirectoryItem $dirItem Item instance
+     * @param LibraryType $libraryType Source library object
+     * @param DirectoryItem $directoryItem Item instance
      * @param FileHistoryItem $fileHistoryItem FileHistory item instance
      * @param string $localFilePath Save file to path. Existing files will be overwritten without warning
      *
-     * @return ResponseInterface
      * @throws GuzzleException
      */
     public function downloadRevision(
-        LibraryType     $library,
-        DirectoryItem   $dirItem,
+        LibraryType     $libraryType,
+        DirectoryItem   $directoryItem,
         FileHistoryItem $fileHistoryItem,
         string          $localFilePath
     ): ResponseInterface
     {
-        $downloadUrl = $this->getFileRevisionDownloadUrl($library, $dirItem, $fileHistoryItem);
+        $downloadUrl = $this->getFileRevisionDownloadUrl($libraryType, $directoryItem, $fileHistoryItem);
 
         return $this->client->request('GET', $downloadUrl, ['save_to' => $localFilePath]);
     }
@@ -515,20 +493,20 @@ public function downloadRevision(
     /**
      * Get history of a file DirectoryItem
      *
-     * @param LibraryType $library Library instance
-     * @param DirectoryItem $item Item instance
+     * @param LibraryType $libraryType Library instance
+     * @param DirectoryItem $directoryItem Item instance
      *
      * @return FileHistoryItem[]
      * @throws GuzzleException
      * @throws Exception
      */
-    public function getHistory(LibraryType $library, DirectoryItem $item)
+    public function getHistory(LibraryType $libraryType, DirectoryItem $directoryItem): array
     {
         $url = $this->getApiBaseUrl()
             . '/repos/'
-            . $library->id
+            . $libraryType->id
             . '/file/history/'
-            . '?p=' . $this->urlEncodePath($item->path . $item->name);
+            . '?p=' . $this->urlEncodePath($directoryItem->path . $directoryItem->name);
 
         $response = $this->client->request('GET', $url);
 
@@ -546,24 +524,23 @@ public function getHistory(LibraryType $library, DirectoryItem $item)
     /**
      * Create empty file on Seafile server
      *
-     * @param LibraryType $library Library instance
-     * @param DirectoryItem $item Item instance
+     * @param LibraryType $libraryType Library instance
+     * @param DirectoryItem $directoryItem Item instance
      *
-     * @return bool
      * @throws GuzzleException
      */
-    public function create(LibraryType $library, DirectoryItem $item): bool
+    public function create(LibraryType $libraryType, DirectoryItem $directoryItem): bool
     {
         // do not allow empty paths
-        if (empty($item->path)) {
+        if (empty($directoryItem->path)) {
             return false;
         }
 
         $uri = sprintf(
             '%s/repos/%s/file/?p=%s',
             $this->clipUri($this->getApiBaseUrl()),
-            $library->id,
-            $this->urlEncodePath($item->path . $item->name)
+            $libraryType->id,
+            $this->urlEncodePath($directoryItem->path . $directoryItem->name)
         );
 
         $response = $this->client->request(
diff --git a/src/Resource/Group.php b/src/Resource/Group.php
index 8f8416a..6573034 100644
--- a/src/Resource/Group.php
+++ b/src/Resource/Group.php
@@ -16,7 +16,7 @@
  */
 class Group extends Resource
 {
-    const API_VERSION = '2';
+    public const API_VERSION = '2';
 
     /**
      * List groups
diff --git a/src/Resource/Library.php b/src/Resource/Library.php
index 892fd4d..0d62d37 100644
--- a/src/Resource/Library.php
+++ b/src/Resource/Library.php
@@ -17,7 +17,7 @@
  */
 class Library extends Resource
 {
-    const API_VERSION = '2';
+    public const API_VERSION = '2';
 
     /**
      * List libraries
@@ -45,10 +45,9 @@ public function getAll(): array
      *
      * @param string $libraryId Library ID
      *
-     * @return LibraryType
      * @throws Exception
      */
-    public function getById($libraryId): LibraryType
+    public function getById(string $libraryId): LibraryType
     {
         $response = $this->client->request(
             'GET',
@@ -70,7 +69,7 @@ public function getById($libraryId): LibraryType
      *
      * @throws Exception
      */
-    public function decrypt($libraryId, array $options): bool
+    public function decrypt(string $libraryId, array $options): bool
     {
         $hasQueryParams = array_key_exists('query', $options);
         $hasPassword = $hasQueryParams && array_key_exists('password', $options['query']);
@@ -94,7 +93,6 @@ public function decrypt($libraryId, array $options): bool
      * @param string $value Library name
      * @param string $attribute Attribute name of library
      *
-     * @return bool
      * @throws Exception
      * @throws GuzzleException
      */
@@ -102,8 +100,8 @@ public function exists($value, $attribute = 'name'): bool
     {
         $libraries = $this->getAll();
 
-        foreach ($libraries as $lib) {
-            if (isset($lib->{$attribute}) && $lib->{$attribute} === $value) {
+        foreach ($libraries as $library) {
+            if (isset($library->{$attribute}) && $library->{$attribute} === $value) {
                 return true;
             }
         }
@@ -118,7 +116,6 @@ public function exists($value, $attribute = 'name'): bool
      * @param string $description Library description
      * @param string $password false means no encryption, any other string is used as password
      *
-     * @return bool
      * @throws Exception
      * @throws GuzzleException
      */
@@ -174,7 +171,6 @@ public function create($name, $description = "new repo", $password = ''): bool
      *
      * @param string $libraryId Library ID
      *
-     * @return bool
      * @throws GuzzleException
      */
     public function remove($libraryId): bool
@@ -207,8 +203,6 @@ public function remove($libraryId): bool
      * @param string $libraryId Library ID
      * @param array $users Comma separated list of user email addresses
      * @param string $permission The permission of the shared library
-     *
-     * @return bool
      */
     public function sharePersonal($libraryId, array $users, string $permission = Resource::PERMISSION_R): bool
     {
@@ -216,7 +210,7 @@ public function sharePersonal($libraryId, array $users, string $permission = Res
             '%s/shared-repos/%s/?share_type=personal&users=%s&permission=%s',
             $this->clipUri($this->getApiBaseUrl()),
             $libraryId,
-            join(',', $users),
+            implode(',', $users),
             $permission
         );
 
diff --git a/src/Resource/Multi.php b/src/Resource/Multi.php
index ab7884b..341c750 100644
--- a/src/Resource/Multi.php
+++ b/src/Resource/Multi.php
@@ -16,17 +16,17 @@
  */
 class Multi extends Resource
 {
-    const API_VERSION = '2';
+    public const API_VERSION = '2';
 
     /**
      * Mode of operation: copy
      */
-    const OPERATION_COPY = 1;
+    public const OPERATION_COPY = 1;
 
     /**
      * Mode of operation: move
      */
-    const OPERATION_MOVE = 2;
+    public const OPERATION_MOVE = 2;
 
     /**
      * Move multiple files or folders
@@ -36,7 +36,6 @@ class Multi extends Resource
      * @param LibraryType $dstLibrary Destination library object
      * @param string $dstDirectoryPath Destination directory Path
      *
-     * @return bool
      * @throws GuzzleException
      */
     public function move(
@@ -58,7 +57,6 @@ public function move(
      * @param string $dstDirectoryPath Destination directory Path
      * @param int $operation self::OPERATION_COPY or self::OPERATION_MOVE
      *
-     * @return bool
      * @throws GuzzleException
      */
     public function copy(
@@ -70,7 +68,7 @@ public function copy(
     ): bool
     {
         // do not allow empty paths
-        if (empty($srcPaths) || empty($dstDirectoryPath)) {
+        if ($srcPaths === [] || ($dstDirectoryPath === '' || $dstDirectoryPath === '0')) {
             return false;
         }
 
@@ -78,11 +76,11 @@ public function copy(
 
         // get the source folder path
         // this path must be the same for all files!
-        $srcFolderPath = dirname($srcPaths[0]);
+        $srcFolderPath = dirname((string) $srcPaths[0]);
 
         $dstFileNames = $this->preparePaths($srcFolderPath, $srcPaths);
 
-        if (empty($dstFileNames)) {
+        if ($dstFileNames === '' || $dstFileNames === '0') {
             return false;
         }
 
@@ -127,19 +125,19 @@ public function copy(
      * @param string $folder Folder path
      * @param array $paths Paths of files
      * @param string $fileNames Optional file names
-     *
-     * @return string
      */
     protected function preparePaths(string $folder, array $paths, string $fileNames = ''): string
     {
         foreach ($paths as $path) {
-            if (dirname($path) != $folder) {
+            if (dirname((string) $path) !== $folder) {
                 return ''; // all source paths must be the same
             }
-            if ($fileNames != '') {
+
+            if ($fileNames !== '') {
                 $fileNames .= ':';
             }
-            $fileNames .= basename($path);
+
+            $fileNames .= basename((string) $path);
         }
 
         return $fileNames;
@@ -148,26 +146,25 @@ protected function preparePaths(string $folder, array $paths, string $fileNames
     /**
      * Delete multiple files or folders
      *
-     * @param LibraryType $library Library object
+     * @param LibraryType $libraryType Library object
      * @param array $paths Array with file and folder paths (they must be in the same folder)
      *
-     * @return bool
      * @throws GuzzleException
      */
-    public function delete(LibraryType $library, array $paths): bool
+    public function delete(LibraryType $libraryType, array $paths): bool
     {
         // do not allow empty paths
-        if (empty($paths)) {
+        if ($paths === []) {
             return false;
         }
 
         // get the folder path
         // this path must be the same for all files!
-        $folderPath = dirname($paths[0]);
+        $folderPath = dirname((string) $paths[0]);
 
         $fileNames = $this->preparePaths($folderPath, $paths);
 
-        if (empty($fileNames)) {
+        if ($fileNames === '' || $fileNames === '0') {
             return false;
         }
 
@@ -176,7 +173,7 @@ public function delete(LibraryType $library, array $paths): bool
         $uri = sprintf(
             '%s/repos/%s/fileops/delete/?p=%s',
             $this->clipUri($this->getApiBaseUrl()),
-            $library->id,
+            $libraryType->id,
             $folderPath
         );
 
diff --git a/src/Resource/Resource.php b/src/Resource/Resource.php
index 64ddc29..40835a4 100644
--- a/src/Resource/Resource.php
+++ b/src/Resource/Resource.php
@@ -15,33 +15,25 @@
  */
 abstract class Resource implements ResourceInterface
 {
-    const API_VERSION = '2.1';
+    public const API_VERSION = '2.1';
 
     /** Represents 'read' permission (in whatever context) */
-    const PERMISSION_R = 'r';
+    public const PERMISSION_R = 'r';
 
     /** Represents 'read and write' permission (in whatever context) */
-    const PERMISSION_RW = 'rw';
-
-    /**
-     * @var Client
-     */
-    protected $client;
+    public const PERMISSION_RW = 'rw';
 
     /**
      * Constructor
      *
      * @param Client $client Client instance
      */
-    public function __construct(Client $client)
+    public function __construct(protected Client $client)
     {
-        $this->client = $client;
     }
 
     /**
      * Get the actual API base URL depending on the resource
-     *
-     * @return string
      */
     public function getApiBaseUrl(): string
     {
@@ -52,8 +44,6 @@ public function getApiBaseUrl(): string
      * Clip tailing slash
      *
      * @param string $uri URI string
-     *
-     * @return mixed|string
      */
     public function clipUri(string $uri): string
     {
diff --git a/src/Resource/ShareLinks.php b/src/Resource/ShareLinks.php
index acafb66..a3c512d 100644
--- a/src/Resource/ShareLinks.php
+++ b/src/Resource/ShareLinks.php
@@ -45,8 +45,6 @@ public function getAll(): array
      * Remove shared link
      *
      * @param SharedLinkType $sharedLinkType SharedLinkType instance
-     *
-     * @return bool
      */
     public function remove(SharedLinkType $sharedLinkType): bool
     {
@@ -76,20 +74,18 @@ public function remove(SharedLinkType $sharedLinkType): bool
     /**
      * Create share link
      *
-     * @param LibraryType $library Library instance
+     * @param LibraryType $libraryType Library instance
      * @param string $path Path
-     * @param SharedLinkPermissions $permissions
      * @param int|null $expire Expire in such many days
      * @param string|null $password Optional password string
      *
-     * @return SharedLinkType|null
      * @throws GuzzleException
      * @throws Exception
      */
     public function create(
-        LibraryType           $library,
+        LibraryType           $libraryType,
         string                $path,
-        SharedLinkPermissions $permissions,
+        SharedLinkPermissions $sharedLinkPermissions,
         int                   $expire = null,
         string                $password = null
     ): ?SharedLinkType
@@ -100,19 +96,19 @@ public function create(
         );
 
         $multiPartParams = [
-            ['name' => 'repo_id', 'contents' => $library->id],
+            ['name' => 'repo_id', 'contents' => $libraryType->id],
             ['name' => 'path', 'contents' => $path],
             [
                 'name' => 'permissions',
                 'contents' => json_encode([
-                    'can_edit' => $permissions->is(SharedLinkPermissions::CAN_EDIT),
-                    'can_download' => $permissions->is(SharedLinkPermissions::CAN_DOWNLOAD)
+                    'can_edit' => $sharedLinkPermissions->is(SharedLinkPermissions::CAN_EDIT),
+                    'can_download' => $sharedLinkPermissions->is(SharedLinkPermissions::CAN_DOWNLOAD)
                 ])
             ]
         ];
 
         if (!is_null($expire)) {
-            $multiPartParams[] = ['name' => 'expire_days', 'contents' => "$expire"];
+            $multiPartParams[] = ['name' => 'expire_days', 'contents' => '' . $expire];
         }
 
         if (!is_null($password)) {
diff --git a/src/Resource/StarredFile.php b/src/Resource/StarredFile.php
index 972514f..a7559f0 100644
--- a/src/Resource/StarredFile.php
+++ b/src/Resource/StarredFile.php
@@ -21,12 +21,9 @@
  */
 class StarredFile extends Resource
 {
-    const API_VERSION = '2';
+    public const API_VERSION = '2';
 
-    /**
-     * @var string
-     */
-    protected $resourceUri = '';
+    protected string $resourceUri;
 
     /**
      * Constructor
@@ -65,15 +62,15 @@ public function getAll(): array
     /**
      * Create directory within $parentDir
      *
-     * @param LibraryType $library Library instance
-     * @param DirectoryItem $dirItem DirectoryItem instance to star
+     * @param LibraryType $libraryType Library instance
+     * @param DirectoryItem $directoryItem DirectoryItem instance to star
      *
      * @return string URL of starred file list
      * @throws Exception
      */
-    public function star(LibraryType $library, DirectoryItem $dirItem): string
+    public function star(LibraryType $libraryType, DirectoryItem $directoryItem): string
     {
-        if ($dirItem->type !== 'file') {
+        if ($directoryItem->type !== 'file') {
             throw new Exception('Cannot star other items than files.');
         }
 
@@ -85,11 +82,11 @@ public function star(LibraryType $library, DirectoryItem $dirItem): string
                 'multipart' => [
                     [
                         'name' => 'repo_id',
-                        'contents' => $library->id,
+                        'contents' => $libraryType->id,
                     ],
                     [
                         'name' => 'p',
-                        'contents' => $dirItem->path,
+                        'contents' => $directoryItem->path,
                     ],
                 ],
             ]
@@ -105,18 +102,16 @@ public function star(LibraryType $library, DirectoryItem $dirItem): string
     /**
      * Unstar a file
      *
-     * @param LibraryType $library Library instance
-     * @param DirectoryItem $dirItem DirectoryItem instance
-     *
-     * @return bool
+     * @param LibraryType $libraryType Library instance
+     * @param DirectoryItem $directoryItem DirectoryItem instance
      */
-    public function unstar(LibraryType $library, DirectoryItem $dirItem): bool
+    public function unstar(LibraryType $libraryType, DirectoryItem $directoryItem): bool
     {
         $uri = sprintf(
             '%s/?repo_id=%s&p=%s',
             $this->resourceUri,
-            $library->id,
-            $dirItem->path
+            $libraryType->id,
+            $directoryItem->path
         );
 
         $response = $this->client->request('DELETE', $uri);
diff --git a/src/Type/Account.php b/src/Type/Account.php
index c3517fb..0f9ac08 100644
--- a/src/Type/Account.php
+++ b/src/Type/Account.php
@@ -18,83 +18,68 @@
  */
 class Account extends Type
 {
-    /**
-     * @var string|null
-     */
-    public $contactEmail = null;
+    public ?string $contactEmail = null;
 
-    /**
-     * @var DateTime|null
-     */
-    public $createTime = null;
+    public ?DateTime $createTime = null;
 
-    /**
-     * @var string|null
-     */
-    public $department = null;
+    public ?string $department = null;
 
-    /**
-     * @var string|null
-     */
-    public $email = null;
+    public ?string $email = null;
 
-    /**
-     * @var int|null
-     */
-    public $id = null;
+    public ?int $id = null;
 
     /**
      * @var string|null
      */
-    public $institution = null;
+    public $institution;
 
     /**
      * @var bool|null
      */
-    public $isStaff = null;
+    public $isStaff;
 
     /**
      * @var bool|null
      */
-    public $isActive = null;
+    public $isActive;
 
     /**
      * @var string|null
      */
-    public $loginId = null;
+    public $loginId;
 
     /**
      * @var string|null
      */
-    public $name = null;
+    public $name;
 
     /**
      * @var string|null
      */
-    public $note = null;
+    public $note;
 
     /**
      * @var string|null
      */
-    public $password = null;
+    public $password;
 
     /**
      * @var int|null
      */
-    public $storage = null;
+    public $storage;
 
     /**
      * @var int|null
      */
-    public $spaceQuota = null;
+    public $spaceQuota;
 
     /**
      * @var int|null
      */
-    public $total = null;
+    public $total;
 
     /**
      * @var int|null
      */
-    public $usage = null;
+    public $usage;
 }
diff --git a/src/Type/Avatar.php b/src/Type/Avatar.php
index 97dad36..4b3fc0a 100644
--- a/src/Type/Avatar.php
+++ b/src/Type/Avatar.php
@@ -21,15 +21,15 @@ class Avatar extends Type
     /**
      * @var string|null
      */
-    public $url = null;
+    public $url;
 
     /**
      * @var bool|null
      */
-    public $isDefault = null;
+    public $isDefault;
 
     /**
      * @var DateTime|null
      */
-    public $mtime = null;
+    public $mtime;
 }
diff --git a/src/Type/DirectoryItem.php b/src/Type/DirectoryItem.php
index 456eafe..7e3a41e 100644
--- a/src/Type/DirectoryItem.php
+++ b/src/Type/DirectoryItem.php
@@ -41,17 +41,17 @@ class DirectoryItem extends Type
     /**
      * @var int|null
      */
-    public $org = null;
+    public $org;
 
     /**
      * @var string|null
      */
-    public $path = null;
+    public $path;
 
     /**
      * @var string|null
      */
-    public $repo = null;
+    public $repo;
 
     /**
      * @var string
@@ -63,15 +63,15 @@ class DirectoryItem extends Type
      */
     public $type = "";
 
-    const TYPE_DIR = 'dir';
-    const TYPE_FILE = 'file';
+    public const TYPE_DIR = 'dir';
+
+    public const TYPE_FILE = 'file';
 
     /**
      * Populate from array
      *
      * @param array $fromArray Create from array
      *
-     * @return DirectoryItem
      * @throws Exception
      */
     public function fromArray(array $fromArray): DirectoryItem
@@ -79,15 +79,15 @@ public function fromArray(array $fromArray): DirectoryItem
         $typeExists = array_key_exists('type', $fromArray);
         $dirExists = array_key_exists('dir', $fromArray);
 
-        if ($typeExists === false && $dirExists === true && is_bool($fromArray['dir'])) {
-            $fromArray['type'] = $fromArray['dir'] === true ? self::TYPE_DIR : self::TYPE_FILE;
+        if ($typeExists === false && $dirExists && is_bool($fromArray['dir'])) {
+            $fromArray['type'] = $fromArray['dir'] ? self::TYPE_DIR : self::TYPE_FILE;
         }
 
         /**
-         * @var self $dirItem
+         * @var self $type
          */
-        $dirItem = parent::fromArray($fromArray);
+        $type = parent::fromArray($fromArray);
 
-        return $dirItem;
+        return $type;
     }
 }
diff --git a/src/Type/FileHistoryItem.php b/src/Type/FileHistoryItem.php
index 557b930..aa36f89 100644
--- a/src/Type/FileHistoryItem.php
+++ b/src/Type/FileHistoryItem.php
@@ -31,7 +31,7 @@ class FileHistoryItem extends Type
     /**
      * @var DateTime|null
      */
-    public $ctime = null;
+    public $ctime;
 
     /**
      * @var string
@@ -95,5 +95,5 @@ class FileHistoryItem extends Type
     /**
      * @var int|null
      */
-    public $secondParentId = null;
+    public $secondParentId;
 }
diff --git a/src/Type/Group.php b/src/Type/Group.php
index 0ef91c5..8e7e50f 100644
--- a/src/Type/Group.php
+++ b/src/Type/Group.php
@@ -21,30 +21,30 @@ class Group extends Type
     /**
      * @var int|null
      */
-    public $ctime = null;
+    public $ctime;
 
     /**
      * @var AccountType|null
      */
-    public $creator = null;
+    public $creator;
 
     /**
      * @var int|null
      */
-    public $msgnum = null;
+    public $msgnum;
 
     /**
      * @var int|null
      */
-    public $mtime = null;
+    public $mtime;
 
     /**
      * @var int|null
      */
-    public $id = null;
+    public $id;
 
     /**
      * @var string|null
      */
-    public $name = null;
+    public $name;
 }
diff --git a/src/Type/SharedLink.php b/src/Type/SharedLink.php
index c8ae61b..4e8b695 100644
--- a/src/Type/SharedLink.php
+++ b/src/Type/SharedLink.php
@@ -23,56 +23,56 @@ class SharedLink extends Type
      *
      * @var int|null
      */
-    public $viewCnt = null;
+    public $viewCnt;
 
     /**
      * Token
      *
      * @var string|null
      */
-    public $token = null;
+    public $token;
 
     /**
      * Creation time
      *
      * @var DateTime|null
      */
-    public $ctime = null;
+    public $ctime;
 
     /**
      * Path
      *
      * @var string|null
      */
-    public $path = null;
+    public $path;
 
     /**
      * Repo ID
      *
      * @var string|null
      */
-    public $repoId = null;
+    public $repoId;
 
     /**
      * User name
      *
      * @var string|null
      */
-    public $username = null;
+    public $username;
 
     /**
      * URL
      *
      * @var string|null
      */
-    public $url = null;
+    public $url;
 
     /**
      * Link, same as URL
      *
      * @var string|null
      */
-    public $link = null;
+    public $link;
 
     /**
      * @var array
@@ -98,5 +98,5 @@ class SharedLink extends Type
     /**
      * @var DateTime|null
      */
-    public $expireDate = null;
+    public $expireDate;
 }
diff --git a/src/Type/SharedLinkPermissions.php b/src/Type/SharedLinkPermissions.php
index 54fd4ef..babd689 100644
--- a/src/Type/SharedLinkPermissions.php
+++ b/src/Type/SharedLinkPermissions.php
@@ -12,6 +12,7 @@
  */
 class SharedLinkPermissions extends AbstractBitmask
 {
-    const CAN_DOWNLOAD = 1;
-    const CAN_EDIT = 2;
+    public const CAN_DOWNLOAD = 1;
+
+    public const CAN_EDIT = 2;
 }
\ No newline at end of file
diff --git a/src/Type/Type.php b/src/Type/Type.php
index 88a9eb8..78a2bdb 100644
--- a/src/Type/Type.php
+++ b/src/Type/Type.php
@@ -22,12 +22,12 @@ abstract class Type implements TypeInterface
     /**
      * Associative array mode
      */
-    const ARRAY_ASSOC = 1;
+    public const ARRAY_ASSOC = 1;
 
     /**
      * Multipart array mode
      */
-    const ARRAY_MULTI_PART = 2;
+    public const ARRAY_MULTI_PART = 2;
 
     /**
      * Constructor
@@ -38,7 +38,7 @@ abstract class Type implements TypeInterface
      */
     public function __construct(array $fromArray = [])
     {
-        if (is_array($fromArray) && !empty($fromArray)) {
+        if ($fromArray !== []) {
             $this->fromArray($fromArray);
         }
     }
@@ -87,8 +87,6 @@ public function fromArray(array $fromArray) // type is given in derived class
      * it's microseconds. You never know.
      *
      * @param int $value Int time stamp, either seconds or microseconds
-     *
-     * @return DateTime
      */
     public function getDateTime(int $value): DateTime
     {
@@ -119,7 +117,6 @@ public function fromJson(stdClass $jsonResponse) // type is given in derived cla
      *
      * @param int $mode Array mode
      *
-     * @return array
      * @throws Exception
      */
     public function toArray(int $mode = self::ARRAY_ASSOC): array
@@ -135,7 +132,7 @@ public function toArray(int $mode = self::ARRAY_ASSOC): array
                         $val = $val->format('U');
                     }
 
-                    $multiPart[] = ['name' => $caseHelper->toSnakeCase($key), 'contents' => "$val"];
+                    $multiPart[] = ['name' => $caseHelper->toSnakeCase($key), 'contents' => $val];
                 }
 
                 $array = $multiPart;
diff --git a/src/Type/TypeInterface.php b/src/Type/TypeInterface.php
index 9a10c53..61d2d43 100644
--- a/src/Type/TypeInterface.php
+++ b/src/Type/TypeInterface.php
@@ -21,14 +21,11 @@ interface TypeInterface
      * @throws Exception
      */
     public function fromArray(array $fromArray); // type is given in implementing class
-
     /**
      * Time stamps vary a lot in Seafile. Sometimes it's seconds from 1970-01-01 00:00:00, sometimes
      * it's microseconds. You never know.
      *
      * @param int $value Int time stamp, either seconds or microseconds
-     *
-     * @return DateTime
      */
     public function getDateTime(int $value): DateTime;
 
@@ -41,13 +38,11 @@ public function getDateTime(int $value): DateTime;
      * @throws Exception
      */
     public function fromJson(stdClass $jsonResponse); // type is given in implementing class
-
     /**
      * Return instance as array
      *
      * @param int $mode Array mode
      *
-     * @return array
      * @throws Exception
      */
     public function toArray(int $mode = Type::ARRAY_ASSOC): array;
diff --git a/test/bootstrap.php b/test/bootstrap.php
index dd80b64..1619c5e 100644
--- a/test/bootstrap.php
+++ b/test/bootstrap.php
@@ -3,7 +3,7 @@
 use Seafile\Client\Http\Client;
 use Seafile\Client\Resource\Auth;
 
-require_once 'vendor/autoload.php';
+require_once __DIR__ . '/../vendor/autoload.php';
 
 $functionalTestsCredentialsComplete = (
     $_ENV['ALLOW_LIVE_DATA_MANIPULATION_ON_TEST_SERVER'] === '1'
@@ -53,6 +53,6 @@
 
 try {
     $GLOBALS['FAKER_SEED'] = random_int(0, 1000000); // @todo Make tests repeatable
-} catch (Exception $e) {
-    die($e->getMessage());
+} catch (Exception $exception) {
+    die($exception->getMessage());
 }
diff --git a/test/functional/FunctionalTestCase.php b/test/functional/FunctionalTestCase.php
index bb2dcf4..05a423d 100644
--- a/test/functional/FunctionalTestCase.php
+++ b/test/functional/FunctionalTestCase.php
@@ -30,16 +30,16 @@
 class FunctionalTestCase extends TestCase
 {
     /** @var Client|null */
-    protected $client = null;
+    protected $client;
 
     /** @var Logger|null */
-    protected $logger = null;
+    protected $logger;
 
     /** @var LibraryType|null */
-    protected $testLib = null;
+    protected $testLib;
 
     /** @var Generator|null|Internet|Lorem|Person */
-    protected $faker = null;
+    protected $faker;
 
     /**
      * Skip functional tests when they do not have been set up correctly. Please refer to README.md on how to set them up.
@@ -48,7 +48,7 @@ class FunctionalTestCase extends TestCase
      *
      * @beforeClass
      */
-    public static function checkFunctionalTestsSetUpCorrectly()
+    public static function checkFunctionalTestsSetUpCorrectly(): void
     {
         if ($GLOBALS['RUN_FUNCTIONAL_TESTS'] !== true) {
             self::markTestSkipped();
@@ -56,7 +56,6 @@ public static function checkFunctionalTestsSetUpCorrectly()
     }
 
     /**
-     * @return Logger
      * @throws Exception
      */
     protected function getLogger(): Logger
@@ -69,7 +68,6 @@ protected function getLogger(): Logger
     }
 
     /**
-     * @return Client
      * @throws Exception
      */
     protected function getClient(): Client
@@ -79,7 +77,7 @@ protected function getClient(): Client
             $stack->push(
                 Middleware::log(
                     $this->getLogger(),
-                    new MessageFormatter("{hostname} {req_header_Authorization} - {req_header_User-Agent} - [{date_common_log}] \"{method} {host}{target} HTTP/{version}\" {code} {res_header_Content-Length} req_body: {req_body} response_body: {res_body}")
+                    new MessageFormatter('{hostname} {req_header_Authorization} - {req_header_User-Agent} - [{date_common_log}] "{method} {host}{target} HTTP/{version}" {code} {res_header_Content-Length} req_body: {req_body} response_body: {res_body}')
                 )
             );
 
@@ -111,7 +109,6 @@ protected function setUp(): void
     }
 
     /**
-     * @return Generator
      * @throws Exception
      */
     protected function getFaker(): Generator
@@ -119,25 +116,24 @@ protected function getFaker(): Generator
         if (is_null($this->faker)) {
             $this->faker = FakerFactory::create();
             $this->faker->seed($GLOBALS['FAKER_SEED']);
-            $this->getLogger()->info("Random generator seed: {$GLOBALS['FAKER_SEED']}");
+            $this->getLogger()->info('Random generator seed: ' . $GLOBALS['FAKER_SEED']);
         }
 
         return $this->faker;
     }
 
     /**
-     * @return LibraryType
      * @throws Exception
      */
     protected function getTestLibraryType(): LibraryType
     {
         if (is_null($this->testLib)) {
             $libId = $_ENV['TEST_LIB_ENCRYPTED_ID'];
-            $libraryResource = new Library($this->client);
-            $this->testLib = $libraryResource->getById($libId);
+            $library = new Library($this->client);
+            $this->testLib = $library->getById($libId);
 
             if ($this->testLib->encrypted === true && array_key_exists('TEST_LIB_ENCRYPTED_PASSWORD', $_ENV)) {
-                self::assertTrue($libraryResource->decrypt(
+                self::assertTrue($library->decrypt(
                     $libId,
                     [
                         'query' => ['password' => $_ENV['TEST_LIB_ENCRYPTED_PASSWORD']],
diff --git a/test/functional/Resource/AccountTest.php b/test/functional/Resource/AccountTest.php
index fa99fd5..385c908 100644
--- a/test/functional/Resource/AccountTest.php
+++ b/test/functional/Resource/AccountTest.php
@@ -4,6 +4,7 @@
 
 use DateTime;
 use Exception;
+use GuzzleHttp\Exception\GuzzleException;
 use Seafile\Client\Resource\Account;
 use Seafile\Client\Type\Account as AccountType;
 use Seafile\Client\Tests\Functional\FunctionalTestCase;
@@ -19,21 +20,19 @@
  */
 class AccountTest extends FunctionalTestCase
 {
-    /** @var string */
-    private $emailAddress = '';
+    private string $emailAddress = '';
 
-    /** @var Account|null */
-    private $accountResource = null;
+    private ?Account $account;
 
     /**
      * @throws Exception
      */
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp();
 
-        $this->emailAddress = 'seafile_php_sdk_functional_test_' . (string)random_int(0, 1000) . $this->faker->safeEmail;
-        $this->accountResource = new Account($this->client);
+        $this->emailAddress = 'seafile_php_sdk_functional_test_' . random_int(0, 1000) . $this->faker->safeEmail;
+        $this->account = new Account($this->client);
     }
 
     /**
@@ -49,14 +48,15 @@ public function setUp(): void
      * and successfully so that's postponed for now.
      *
      * @throws Exception
+     * @throws GuzzleException
      */
-    public function testAccount()
+    public function testAccount(): void
     {
         $this->logger->debug("#################### Get all users");
-        $accountTypes = $this->accountResource->getAll();
+        $accountTypes = $this->account->getAll();
 
         self::assertIsArray($accountTypes);
-        self::assertTrue(count($accountTypes) > 0);
+        self::assertTrue($accountTypes !== []);
 
         foreach ($accountTypes as $accountType) {
             $this->logger->debug($accountType->email);
@@ -64,14 +64,14 @@ public function testAccount()
             self::assertInstanceOf(AccountType::class, $accountType);
             self::assertIsString(
                 filter_var($accountType->email, FILTER_VALIDATE_EMAIL),
-                "Expected a valid email address but got '{$accountType->email}'"
+                sprintf("Expected a valid email address but got '%s'", $accountType->email)
             );
         }
 
         $fullUserName = $this->faker->name();
         $note = $this->faker->sentence();
 
-        $this->logger->debug("#################### Create random account: {$this->emailAddress}");
+        $this->logger->debug('#################### Create random account: ' . $this->emailAddress);
 
         $newAccountType = (new AccountType)->fromArray([
             'email' => $this->emailAddress,
@@ -82,11 +82,11 @@ public function testAccount()
             //'institution' => 'Duff Beer Inc.',
         ]);
 
-        self::assertTrue($this->accountResource->create($newAccountType));
+        self::assertTrue($this->account->create($newAccountType));
 
         // get info on specific user
-        $this->logger->debug("#################### Get AccountType instance by email address: {$this->emailAddress}");
-        $accountType = $this->accountResource->getByEmail($this->emailAddress);
+        $this->logger->debug('#################### Get AccountType instance by email address: ' . $this->emailAddress);
+        $accountType = $this->account->getByEmail($this->emailAddress);
 
         self::assertInstanceOf(AccountType::class, $accountType);
         self::assertSame($this->emailAddress, $accountType->email);
@@ -99,8 +99,8 @@ public function testAccount()
             }
         }
 
-        $this->logger->debug("#################### Get Account info by email address: {$this->emailAddress}");
-        $accountType = $this->accountResource->getInfo($this->emailAddress);
+        $this->logger->debug('#################### Get Account info by email address: ' . $this->emailAddress);
+        $accountType = $this->account->getInfo($this->emailAddress);
 
         self::assertInstanceOf(AccountType::class, $accountType);
         self::assertSame($this->emailAddress, $accountType->email);
diff --git a/test/functional/Resource/FileTest.php b/test/functional/Resource/FileTest.php
index 548b7da..229ba2f 100644
--- a/test/functional/Resource/FileTest.php
+++ b/test/functional/Resource/FileTest.php
@@ -2,6 +2,7 @@
 
 namespace Seafile\Client\Tests\Functional\Resource;
 
+use Carbon\Carbon;
 use Exception;
 use GuzzleHttp\Exception\GuzzleException;
 use Seafile\Client\Resource\Directory;
@@ -21,20 +22,18 @@
  */
 class FileTest extends FunctionalTestCase
 {
-    /** @var File|null */
-    private $fileResource = null;
+    private ?File $file;
 
-    /** @var Library|null */
-    private $libraryResource = null;
+    private ?\Seafile\Client\Type\Library $library = null;
 
     /**
      * @throws Exception
      */
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp();
 
-        $this->fileResource = new File($this->client);
+        $this->file = new File($this->client);
     }
 
     /**
@@ -43,13 +42,13 @@ public function setUp(): void
      * @throws Exception
      * @throws GuzzleException
      */
-    public function testCreate()
+    public function testCreate(): void
     {
         $this->logger->debug("#################### Create empty file on Seafile server.");
 
-        $dirItem = (new DirectoryItem())->fromArray(['path' => '/', 'name' => uniqid('some_name_', true) . '.txt']);
+        $directoryItem = (new DirectoryItem())->fromArray(['path' => '/', 'name' => uniqid('some_name_', true) . '.txt']);
 
-        self::assertTrue($this->fileResource->create($this->getTestLibraryType(), $dirItem));
+        self::assertTrue($this->file->create($this->getTestLibraryType(), $directoryItem));
     }
 
     /**
@@ -69,41 +68,41 @@ public function testCreate()
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testHistory()
+    public function testHistory(): void
     {
-        $lib = $this->getTestLibraryType();
+        $library = $this->getTestLibraryType();
 
-        $this->logger->debug("#################### Getting lib with ID " . $lib->id);
+        $this->logger->debug("#################### Getting lib with ID " . $library->id);
 
         // upload a Hello World file and random file name (note: this seems not to work at this time when you are not logged into the Seafile web frontend).
         $newFilename = tempnam($GLOBALS['BUILD_TMP'], 'Seafile-PHP-SDK_Test_File_History_Upload_');
         rename($newFilename, $newFilename . '.txt');
         $newFilename .= '.txt';
-        file_put_contents($newFilename, 'Hello World: ' . date('Y-m-d H:i:s'));
+        file_put_contents($newFilename, 'Hello World: ' . Carbon::now()->format('Y-m-d H:i:s'));
 
         $this->logger->debug("#################### Uploading file " . $newFilename);
 
-        $response = $this->fileResource->upload($lib, $newFilename, '/');
+        $response = $this->file->upload($library, $newFilename, '/');
         self::assertSame(200, $response->getStatusCode());
 
         // Update file
         $this->logger->debug("#################### Updating file " . $newFilename);
         file_put_contents($newFilename, ' - UPDATED!', FILE_APPEND);
-        $response = $this->fileResource->update($lib, $newFilename, '/');
+        $response = $this->file->update($library, $newFilename, '/');
 
         self::assertSame(200, $response->getStatusCode());
 
         // Get file detail
         $this->logger->debug("#################### Getting file detail of " . $newFilename);
-        $dirItem = $this->fileResource->getFileDetail($lib, basename($newFilename));
+        $directoryItem = $this->file->getFileDetail($library, basename($newFilename));
 
-        if ($dirItem->path === null) {
-            $dirItem->path = '/';
+        if ($directoryItem->path === null) {
+            $directoryItem->path = '/';
         }
 
         // Get file history
         $this->logger->debug("#################### Getting file history of " . $newFilename);
-        $fileHistoryItems = $this->fileResource->getHistory($lib, $dirItem);
+        $fileHistoryItems = $this->file->getHistory($library, $directoryItem);
 
         $this->logger->debug("#################### Listing file history of " . $newFilename);
 
@@ -116,12 +115,12 @@ public function testHistory()
         $firstFileRevision = array_slice($fileHistoryItems, -1)[0];
 
         $localFilePath = $GLOBALS['BUILD_TMP'] . '/yo.txt';
-        $response = $this->fileResource->downloadRevision($lib, $dirItem, $firstFileRevision, $localFilePath);
+        $response = $this->file->downloadRevision($library, $directoryItem, $firstFileRevision, $localFilePath);
 
         self::assertSame(200, $response->getStatusCode());
 
         $this->logger->debug(
-            "#### First file revision of " . $dirItem->name . " downloaded to " . $localFilePath
+            "#### First file revision of " . $directoryItem->name . " downloaded to " . $localFilePath
         );
     }
 
@@ -131,19 +130,19 @@ public function testHistory()
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testList()
+    public function testList(): void
     {
         $desiredDirectoryPath = '/';
-        $lib = $this->getTestLibraryType();
+        $library = $this->getTestLibraryType();
 
         // get all directory items and list them one by one.
         $directory = new Directory($this->client);
-        $items = $directory->getAll($lib, $desiredDirectoryPath);
+        $items = $directory->getAll($library, $desiredDirectoryPath);
 
         $this->logger->debug("############################################### Result:");
 
         self::assertIsArray($items);
-        self::assertTrue(count($items) > 0);
+        self::assertTrue($items !== []);
 
         foreach ($items as $item) {
             $this->logger->debug(sprintf("(%s) %s/%s (%d bytes)\n", $item->type, $item->path, $item->name, $item->size));
@@ -157,14 +156,14 @@ public function testList()
      * @throws Exception
      * @throws GuzzleException
      */
-    public function testRename()
+    public function testRename(): void
     {
-        $this->libraryResource = $this->getTestLibraryType();
+        $this->library = $this->getTestLibraryType();
         $libId = $_ENV['TEST_LIB_ENCRYPTED_ID'];
-        $lib = $this->getTestLibraryType();
+        $library = $this->getTestLibraryType();
 
-        if ($lib->encrypted === true && isset($cfg->testLibPassword)) {
-            $success = $this->libraryResource->decrypt($libId, ['query' => ['password' => $_ENV['TEST_LIB_ENCRYPTED_PASSWORD']]]);
+        if ($library->encrypted === true && isset($cfg->testLibPassword)) {
+            $success = $this->library->decrypt($libId, ['query' => ['password' => $_ENV['TEST_LIB_ENCRYPTED_PASSWORD']]]);
             self::assertTrue($success);
         }
 
@@ -174,20 +173,20 @@ public function testRename()
         $fileName = 'test.txt';
 
         $dirItem = (new DirectoryItem())->fromArray(['path' => '/', 'name' => $fileName]);
-        $success = $this->fileResource->create($lib, $dirItem);
+        $success = $this->file->create($library, $dirItem);
         self::assertTrue($success);
 
-        $newFilename = 'test_' . date('U') . '.txt';
-        $dirItem = $this->fileResource->getFileDetail($lib, $path . $fileName);
+        $newFilename = 'test_' . Carbon::now()->format('U') . '.txt';
+        $dirItem = $this->file->getFileDetail($library, $path . $fileName);
 
         $this->logger->debug("#################### File to be renamed: " . $path . $dirItem->name);
 
-        $success = $this->fileResource->rename($lib, $dirItem, $newFilename);
+        $success = $this->file->rename($library, $dirItem, $newFilename);
         self::assertTrue($success);
         $this->logger->debug("#################### File renamed from " . $path . $fileName . ' to ' . $newFilename);
 
-        $newFilename = 'even_newer_file_name_test_' . date('U') . '.txt';
-        $success = $this->fileResource->rename($lib, $dirItem, $newFilename);
+        $newFilename = 'even_newer_file_name_test_' . Carbon::now()->format('U') . '.txt';
+        $success = $this->file->rename($library, $dirItem, $newFilename);
 
         self::assertTrue($success);
         $this->logger->debug("#################### File renamed from " . $dirItem->name . ' to ' . $newFilename);
diff --git a/test/functional/Resource/GroupTest.php b/test/functional/Resource/GroupTest.php
index 2ba97f2..93b2d3d 100644
--- a/test/functional/Resource/GroupTest.php
+++ b/test/functional/Resource/GroupTest.php
@@ -18,17 +18,16 @@
  */
 class GroupTest extends FunctionalTestCase
 {
-    /** @var Group|null */
-    private $groupResource = null;
+    private ?Group $group;
 
     /**
      * @throws Exception
      */
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp();
 
-        $this->groupResource = new Group($this->client);
+        $this->group = new Group($this->client);
     }
 
     /**
@@ -36,14 +35,14 @@ public function setUp(): void
      *
      * @throws Exception
      */
-    public function testGetAll()
+    public function testGetAll(): void
     {
         $this->logger->debug("#################### Get all groups ");
 
-        $groups = $this->groupResource->getAll();
+        $groups = $this->group->getAll();
 
         self::assertIsArray($groups);
-        self::assertTrue(count($groups) > 0);
+        self::assertTrue($groups !== []);
 
         foreach ($groups as $group) {
             $this->logger->debug("#################### " . sprintf("Group name: %s", $group->name));
diff --git a/test/functional/Resource/ShareLinksTest.php b/test/functional/Resource/ShareLinksTest.php
index 25404cc..6a68a9a 100644
--- a/test/functional/Resource/ShareLinksTest.php
+++ b/test/functional/Resource/ShareLinksTest.php
@@ -2,6 +2,7 @@
 
 namespace Seafile\Client\Tests\Functional\Resource;
 
+use Carbon\Carbon;
 use Exception;
 use Seafile\Client\Resource\File;
 use Seafile\Client\Resource\Library;
@@ -22,17 +23,16 @@
  */
 class ShareLinksTest extends FunctionalTestCase
 {
-    /** @var ShareLinksAlias|null */
-    private $shareLinksResource = null;
+    private ?ShareLinksAlias $shareLinksAlias;
 
     /**
      * @throws Exception
      */
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp();
 
-        $this->shareLinksResource = new ShareLinksAlias($this->client);
+        $this->shareLinksAlias = new ShareLinksAlias($this->client);
     }
 
     /**
@@ -44,14 +44,14 @@ public function setUp(): void
      *
      * @throws Exception
      */
-    public function testShareLinks()
+    public function testShareLinks(): void
     {
-        $libraryResource = new Library($this->client);
-        $fileResource = new File($this->client);
+        $library = new Library($this->client);
+        $file = new File($this->client);
 
         // get all libraries available
         $this->logger->debug("#################### Getting all libraries");
-        $libs = $libraryResource->getAll();
+        $libs = $library->getAll();
 
         foreach ($libs as $lib) {
             self::assertInstanceOf(LibraryType::class, $lib);
@@ -62,43 +62,43 @@ public function testShareLinks()
 
         // get specific library
         $this->logger->debug("#################### Getting lib with ID " . $libId);
-        $lib = $libraryResource->getById($libId);
+        $lib = $library->getById($libId);
 
         // upload a Hello World file and random file name (note: this seems not to work at this time when you are not logged into the Seafile web frontend).
         $newFilename = $GLOBALS['BUILD_TMP'] . '/Seafile-PHP-SDK_Test_Upload.txt';
 
         if (!file_exists($newFilename)) {
-            file_put_contents($newFilename, 'Hello World: ' . date('Y-m-d H:i:s'));
+            file_put_contents($newFilename, 'Hello World: ' . Carbon::now()->format('Y-m-d H:i:s'));
         }
 
         $this->logger->debug("#################### Uploading file " . $newFilename);
-        $response = $fileResource->upload($lib, $newFilename, '/');
+        $response = $file->upload($lib, $newFilename, '/');
         self::assertSame(200, $response->getStatusCode());
 
         // create share link for a file
         $this->logger->debug("#################### Create share link for a file");
 
         $expire = 5;
-        $permissions = new SharedLinkPermissions(SharedLinkPermissions::CAN_DOWNLOAD);
+        $sharedLinkPermissions = new SharedLinkPermissions(SharedLinkPermissions::CAN_DOWNLOAD);
         $p = "/" . basename($newFilename);
 
         if ($lib->encrypted) {
-            $shareLinkType = $this->shareLinksResource->create($lib, $p, $permissions, $expire, $lib->password);
+            $shareLinkType = $this->shareLinksAlias->create($lib, $p, $sharedLinkPermissions, $expire, $lib->password);
         } else {
-            $shareLinkType = $this->shareLinksResource->create($lib, $p, $permissions, $expire);
+            $shareLinkType = $this->shareLinksAlias->create($lib, $p, $sharedLinkPermissions, $expire);
         }
 
         self::assertInstanceOf(SharedLink::class, $shareLinkType);
 
         $this->logger->debug("#################### Get all shared links");
-        $shareLinks = $this->shareLinksResource->getAll();
+        $shareLinks = $this->shareLinksAlias->getAll();
 
         self::assertIsArray($shareLinks);
 
         $this->logger->debug("#################### Sleeping 10s before deleting the shared link");
         sleep(1);
 
-        $success = $this->shareLinksResource->remove($shareLinkType);
+        $success = $this->shareLinksAlias->remove($shareLinkType);
         self::assertTrue($success);
 
         $this->logger->debug("#################### Shared link deleted");
diff --git a/test/functional/Resource/StarredFileTest.php b/test/functional/Resource/StarredFileTest.php
index 546c3d8..e0d996a 100644
--- a/test/functional/Resource/StarredFileTest.php
+++ b/test/functional/Resource/StarredFileTest.php
@@ -23,17 +23,16 @@
  */
 class StarredFileTest extends FunctionalTestCase
 {
-    /** @var StarredFile|null */
-    private $starredFileResource = null;
+    private ?StarredFile $starredFile;
 
     /**
      * @throws Exception
      */
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp();
 
-        $this->starredFileResource = new StarredFile($this->client);
+        $this->starredFile = new StarredFile($this->client);
     }
 
     /**
@@ -46,38 +45,38 @@ public function setUp(): void
      * @throws Exception
      * @throws GuzzleException
      */
-    public function testStarFile()
+    public function testStarFile(): void
     {
-        $fileResource = new File($this->client);
-        $libraryResource = new Library($this->client);
+        $file = new File($this->client);
+        $library = new Library($this->client);
 
-        $dirItem = (new DirectoryItem())->fromArray(['path' => '/', 'name' => uniqid('some_name_', true) . '.txt']);
-        self::assertTrue($fileResource->create($this->getTestLibraryType(), $dirItem));
-        $dirItem->type = DirectoryItem::TYPE_FILE;
-        $dirItem->path .= $dirItem->name; // @todo This needs to be done automatically
-        $result = $this->starredFileResource->star($this->getTestLibraryType(), $dirItem);
+        $directoryItem = (new DirectoryItem())->fromArray(['path' => '/', 'name' => uniqid('some_name_', true) . '.txt']);
+        self::assertTrue($file->create($this->getTestLibraryType(), $directoryItem));
+        $directoryItem->type = DirectoryItem::TYPE_FILE;
+        $directoryItem->path .= $directoryItem->name; // @todo This needs to be done automatically
+        $result = $this->starredFile->star($this->getTestLibraryType(), $directoryItem);
         self::assertIsString($result);
 
         // get all starred files
         $this->logger->debug("#################### Getting all starred files");
-        $dirItems = $this->starredFileResource->getAll();
+        $dirItems = $this->starredFile->getAll();
 
         self::assertIsArray($dirItems);
-        self::assertTrue(count($dirItems) > 0); // we just have created one so there must not be 0 items
+        self::assertTrue($dirItems !== []); // we just have created one so there must not be 0 items
 
-        foreach ($dirItems as $dirItem) {
-            self::assertInstanceOf(DirectoryItem::class, $dirItem);
+        foreach ($dirItems as $directoryItem) {
+            self::assertInstanceOf(DirectoryItem::class, $directoryItem);
         }
 
         $this->logger->debug("#################### Unstarring files...");
         foreach ($dirItems as $dirItem) {
-            $lib = $libraryResource->getById($dirItem->repo);
-            $this->starredFileResource->unstar($lib, $dirItem);
+            $lib = $library->getById($dirItem->repo);
+            $this->starredFile->unstar($lib, $dirItem);
         }
 
         // get all starred files, there must be none
         $this->logger->debug("#################### Getting all starred files");
-        $dirItems = $this->starredFileResource->getAll();
-        self::assertFalse(count($dirItems) > 0);
+        $dirItems = $this->starredFile->getAll();
+        self::assertFalse($dirItems !== []);
     }
 }
diff --git a/test/unit/Http/ClientUnitTest.php b/test/unit/Http/ClientUnitTest.php
index f0be3ff..6f12d2f 100644
--- a/test/unit/Http/ClientUnitTest.php
+++ b/test/unit/Http/ClientUnitTest.php
@@ -19,10 +19,8 @@ class ClientUnitTest extends UnitTestCase
 {
     /**
      * Test that base_uri is empty by default.
-     *
-     * @return void
      */
-    public function testBaseUriEmpty()
+    public function testBaseUriEmpty(): void
     {
         $client = new Client();
         self::assertEmpty((string)$client->getConfig('base_uri'));
@@ -30,10 +28,8 @@ public function testBaseUriEmpty()
 
     /**
      * Test that base_uri not empty when a value has been set.
-     *
-     * @return void
      */
-    public function testBaseUriNotEmpty()
+    public function testBaseUriNotEmpty(): void
     {
         $client = new Client(['base_uri' => 'http://example.com']);
         self::assertSame('http://example.com', (string)$client->getConfig('base_uri'));
diff --git a/test/unit/Resource/AccountTest.php b/test/unit/Resource/AccountTest.php
index 2ca19cc..add0046 100644
--- a/test/unit/Resource/AccountTest.php
+++ b/test/unit/Resource/AccountTest.php
@@ -3,6 +3,7 @@
 namespace Seafile\Client\Tests\Unit\Resource;
 
 use DateTime;
+use DateTimeInterface;
 use Exception;
 use GuzzleHttp\Exception\GuzzleException;
 use GuzzleHttp\Psr7\Response;
@@ -27,13 +28,12 @@ class AccountTest extends UnitTestCase
     /**
      * Test getAll()
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testGetAll()
+    public function testGetAll(): void
     {
-        $accountResource = new Account($this->getMockedClient(
+        $account = new Account($this->getMockedClient(
             new Response(
                 200,
                 ['Content-Type' => 'application/json'],
@@ -41,7 +41,7 @@ public function testGetAll()
             )
         ));
 
-        $libs = $accountResource->getAll();
+        $libs = $account->getAll();
 
         self::assertIsArray($libs);
 
@@ -54,12 +54,10 @@ public function testGetAll()
      * Test getByEmail()
      *
      * @param string $method Name of method to be tested
-     *
-     * @return void
      */
-    public function testGetByEmail(string $method = 'getByEmail')
+    public function testGetByEmail(string $method = 'getByEmail'): void
     {
-        $accountResource = new Account($this->getMockedClient(
+        $account = new Account($this->getMockedClient(
             new Response(
                 200,
                 ['Content-Type' => 'application/json'],
@@ -69,20 +67,18 @@ public function testGetByEmail(string $method = 'getByEmail')
 
         $email = 'test-5690113abbceb4.93776759@example.com';
 
-        $accountType = $accountResource->{$method}($email);
+        $accountType = $account->{$method}($email);
 
         self::assertInstanceOf(AccountType::class, $accountType);
         self::assertSame($email, $accountType->email);
         self::assertInstanceOf(DateTime::class, $accountType->createTime);
-        self::assertSame('2016-01-08T19:42:50+0000', $accountType->createTime->format(DATE_ISO8601));
+        self::assertSame('2016-01-08T19:42:50+00:00', $accountType->createTime->format(DateTimeInterface::ATOM));
     }
 
     /**
      * Test getInfo()
-     *
-     * @return void
      */
-    public function testGetInfo()
+    public function testGetInfo(): void
     {
         $this->testGetByEmail('getInfo');
     }
@@ -90,19 +86,16 @@ public function testGetInfo()
     /**
      * Test create() with missing attribute values
      *
-     * @return void
      * @throws Exception
      */
-    public function testCreateIllegal()
+    public function testCreateIllegal(): void
     {
-        $accountResource = new Account($this->getMockedClient(new Response(200)));
-        self::assertFalse($accountResource->create(new AccountType()));
+        $account = new Account($this->getMockedClient(new Response(200)));
+        self::assertFalse($account->create(new AccountType()));
     }
 
     /**
      * Data Provider for testCreate()
-     *
-     * @return array
      */
     public static function dataProviderCreateUpdate(): array
     {
@@ -123,10 +116,9 @@ public static function dataProviderCreateUpdate(): array
      *
      * @param array $data DataProvider data
      *
-     * @return void
      * @throws Exception
      */
-    public function testCreateUpdate(array $data)
+    public function testCreateUpdate(array $data): void
     {
         $baseUri = 'https://example.com';
 
@@ -148,27 +140,24 @@ public function testCreateUpdate(array $data)
             ->with('base_uri')
             ->willReturn($baseUri);
 
-        $accountResource = new Account($mockedClient);
+        $account = new Account($mockedClient);
 
-        self::assertSame($data['result'], $accountResource->{$data['method']}($accountType));
+        self::assertSame($data['result'], $account->{$data['method']}($accountType));
     }
 
     /**
      * Test update() with missing attribute values
      *
-     * @return void
      * @throws Exception
      */
-    public function testUpdateIllegal()
+    public function testUpdateIllegal(): void
     {
-        $accountResource = new Account($this->getMockedClient(new Response(200)));
-        self::assertFalse($accountResource->update(new AccountType()));
+        $account = new Account($this->getMockedClient(new Response(200)));
+        self::assertFalse($account->update(new AccountType()));
     }
 
     /**
      * Data Provider for testRemove()
-     *
-     * @return array
      */
     public static function dataProviderRemove(): array
     {
@@ -185,10 +174,9 @@ public static function dataProviderRemove(): array
      *
      * @param array $data DataProvider data
      *
-     * @return void
      * @throws Exception
      */
-    public function testRemove(array $data)
+    public function testRemove(array $data): void
     {
         $baseUri = 'https://example.com';
 
diff --git a/test/unit/Resource/AvatarTest.php b/test/unit/Resource/AvatarTest.php
index 0666652..12cd432 100644
--- a/test/unit/Resource/AvatarTest.php
+++ b/test/unit/Resource/AvatarTest.php
@@ -27,10 +27,8 @@ class AvatarTest extends UnitTestCase
 {
     /**
      * Test getUserAvatarByEmail()
-     *
-     * @return void
      */
-    public function testGetUserAvatarByEmail()
+    public function testGetUserAvatarByEmail(): void
     {
         $baseUri = 'https://example.com';
         $resource = 'user';
@@ -42,10 +40,8 @@ public function testGetUserAvatarByEmail()
 
     /**
      * Test getAvatar() with illegal avatar size
-     *
-     * @return void
      */
-    public function testGetAvatarIllegalSize()
+    public function testGetAvatarIllegalSize(): void
     {
         $baseUri = 'https://example.com';
         $resource = 'user';
@@ -60,10 +56,9 @@ public function testGetAvatarIllegalSize()
     /**
      * Test getGroupAvatarByEmail()
      *
-     * @return void
      * @throws Exception
      */
-    public function testGetGroupAvatarByEmail()
+    public function testGetGroupAvatarByEmail(): void
     {
         $baseUri = 'https://example.com';
         $resource = 'group';
@@ -107,9 +102,9 @@ protected function doGetAvatar(string $method, string $baseUri, string $resource
             ->with('base_uri')
             ->willReturn($baseUri);
 
-        $avatarResource = new AvatarResource($mockedClient);
+        $avatar = new AvatarResource($mockedClient);
 
-        $avatarType = $avatarResource->{$method}($entity, $size);
+        $avatarType = $avatar->{$method}($entity, $size);
 
         self::assertInstanceOf(Avatar::class, $avatarType);
         self::assertInstanceOf(DateTime::class, $avatarType->mtime);
@@ -119,28 +114,27 @@ protected function doGetAvatar(string $method, string $baseUri, string $resource
     /**
      * Test getAvatar() with illegal type instance
      *
-     * @return void
      * @throws Exception
      */
-    public function testGetAvatarIllegalType()
+    public function testGetAvatarIllegalType(): void
     {
         $baseUri = 'https://example.com';
 
         /** @var SeafileHttpClient|MockObject $mockedClient */
         $mockedClient = $this->getMockBuilder(SeafileHttpClient::class)->getMock();
 
-        $libraryType = new LibraryType();
+        $library = new LibraryType();
 
         $mockedClient->expects(self::any())
             ->method('getConfig')
             ->with('base_uri')
             ->willReturn($baseUri);
 
-        $avatarResource = new AvatarResource($mockedClient);
+        $avatar = new AvatarResource($mockedClient);
 
         $this->expectException('Exception');
         $this->expectExceptionMessage('Unsupported type to retrieve avatar information for.');
 
-        $this->invokeMethod($avatarResource, 'getAvatar', [$libraryType, 80]);
+        $this->invokeMethod($avatar, 'getAvatar', [$library, 80]);
     }
 }
diff --git a/test/unit/Resource/DirectoryTest.php b/test/unit/Resource/DirectoryTest.php
index 92faba9..5bc48e3 100644
--- a/test/unit/Resource/DirectoryTest.php
+++ b/test/unit/Resource/DirectoryTest.php
@@ -27,12 +27,11 @@ class DirectoryTest extends UnitTestCase
     /**
      * Test getAll()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testGetAll()
+    public function testGetAll(): void
     {
-        $directoryResource = new Directory($this->getMockedClient(
+        $directory = new Directory($this->getMockedClient(
             new Response(
                 200,
                 ['Content-Type' => 'application/json'],
@@ -40,7 +39,7 @@ public function testGetAll()
             )
         ));
 
-        $directoryItems = $directoryResource->getAll(new Library());
+        $directoryItems = $directory->getAll(new Library());
 
         self::assertIsArray($directoryItems);
 
@@ -52,10 +51,9 @@ public function testGetAll()
     /**
      * Test getAll() with directory path
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testGetAllWithDir()
+    public function testGetAllWithDir(): void
     {
         $rootDir = '/' . uniqid('test_', true);
 
@@ -78,21 +76,20 @@ public function testGetAllWithDir()
                 self::equalTo(['query' => ['p' => $rootDir]])
             )->willReturn($response);
 
-        $directoryResource = new Directory($mockedClient);
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $directory = new Directory($mockedClient);
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
-        $directoryResource->getAll($lib, $rootDir);
+        $directory->getAll($library, $rootDir);
     }
 
     /**
      * Test exists()
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testExists()
+    public function testExists(): void
     {
         $rootDir = '/' . uniqid('test_', true);
 
@@ -116,23 +113,21 @@ public function testExists()
                 self::equalTo(['query' => ['p' => $rootDir]])
             )->willReturn($response);
 
-        $directoryResource = new Directory($mockedClient);
+        $directory = new Directory($mockedClient);
 
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
-        self::assertFalse($directoryResource->exists($lib, 'does_not_exist', $rootDir)); // ...2nd request...
+        self::assertFalse($directory->exists($library, 'does_not_exist', $rootDir)); // ...2nd request...
 
         // ...3rd request. For 'test_dir' see mock response json file, it's there
-        self::assertTrue($directoryResource->exists($lib, 'test_dir', $rootDir));
+        self::assertTrue($directory->exists($library, 'test_dir', $rootDir));
     }
 
     /**
      * Data provider for testCreateNonRecursive()
-     *
-     * @return array
      */
-    public function createNonRecursiveDataProvider()
+    public function createNonRecursiveDataProvider(): array
     {
         return [[201], [500]];
     }
@@ -143,10 +138,9 @@ public function createNonRecursiveDataProvider()
      * @param int $expectResponseCode Expected mkdir request response code
      *
      * @dataProvider createNonRecursiveDataProvider
-     * @return void
      * @throws GuzzleException
      */
-    public function testCreateNonRecursive(int $expectResponseCode)
+    public function testCreateNonRecursive(int $expectResponseCode): void
     {
         $getAllResponse = new Response(
             200,
@@ -157,13 +151,13 @@ public function testCreateNonRecursive(int $expectResponseCode)
         $mkdirResponse = new Response($expectResponseCode, ['Content-Type' => 'text/plain']);
         $directoryResource = $this->getDirectoryResource($getAllResponse, $mkdirResponse);
 
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
         if ($expectResponseCode === 201) {
-            self::assertTrue($directoryResource->create($lib, 'new_dir', '/', false));
+            self::assertTrue($directoryResource->create($library, 'new_dir', '/', false));
         } else {
-            self::assertFalse($directoryResource->create($lib, 'new_dir', '/', false));
+            self::assertFalse($directoryResource->create($library, 'new_dir', '/', false));
         }
     }
 
@@ -172,10 +166,8 @@ public function testCreateNonRecursive(int $expectResponseCode)
      *
      * @param Response $getAllResponse Response on "get all" request
      * @param Response $mkdirResponse Response on actual operation
-     *
-     * @return Directory
      */
-    protected function getDirectoryResource(Response $getAllResponse, Response $mkdirResponse)
+    protected function getDirectoryResource(Response $getAllResponse, Response $mkdirResponse): Directory
     {
         /** @var SeafileHttpClient|MockObject $mockedClient */
         $mockedClient = $this->getMockBuilder(SeafileHttpClient::class)->getMock();
@@ -205,10 +197,9 @@ function ($method) use ($getAllResponse, $mkdirResponse) {
     /**
      * Test create() non-recursively, directory exists. Must yield boolean false.
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testCreateDirectoryExists()
+    public function testCreateDirectoryExists(): void
     {
         $getAllResponse = new Response(
             200,
@@ -225,30 +216,27 @@ public function testCreateDirectoryExists()
             ->method('request')
             // Return what was passed to offsetGet as a new instance
             ->will(self::returnCallback(
-                function () use ($getAllResponse) {
-                    return $getAllResponse;
-                }
+                fn(): Response => $getAllResponse
             ));
 
-        $directoryResource = new Directory($mockedClient);
+        $directory = new Directory($mockedClient);
 
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
-        self::assertFalse($directoryResource->create($lib, 'test_dir', '/', false));
+        self::assertFalse($directory->create($library, 'test_dir', '/', false));
     }
 
     /**
      * test create() with empty dirName. Must yield boolean false.
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testCreateEmptyDirName()
+    public function testCreateEmptyDirName(): void
     {
-        $directoryResource = new Directory(new SeafileHttpClient());
+        $directory = new Directory(new SeafileHttpClient());
 
-        self::assertFalse($directoryResource->create(
+        self::assertFalse($directory->create(
             new Library(),
             ''
         ));
@@ -257,10 +245,9 @@ public function testCreateEmptyDirName()
     /**
      * Test create() recursively
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testCreateRecursive()
+    public function testCreateRecursive(): void
     {
         $getAllResponse = new Response(
             200,
@@ -271,34 +258,32 @@ public function testCreateRecursive()
         $mkdirResponse = new Response(201, ['Content-Type' => 'text/plain']);
         $directoryResource = $this->getDirectoryResource($getAllResponse, $mkdirResponse);
 
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
-        self::assertTrue($directoryResource->create($lib, 'a/b', '/', true));
+        self::assertTrue($directoryResource->create($library, 'a/b', '/', true));
     }
 
     /**
      * Test rename(), with invalid directory name
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testRenameInvalidDirectoryName()
+    public function testRenameInvalidDirectoryName(): void
     {
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
-        $directoryResource = new Directory(new SeafileHttpClient());
-        self::assertFalse($directoryResource->rename($lib, '', ''));
+        $directory = new Directory(new SeafileHttpClient());
+        self::assertFalse($directory->rename($library, '', ''));
     }
 
     /**
      * Test rename()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testRename()
+    public function testRename(): void
     {
         $getAllResponse = new Response(
             200,
@@ -349,36 +334,34 @@ function ($method, $uri, $params) use ($getAllResponse, $mkdirResponse, $expectU
                 }
             ));
 
-        $directoryResource = new Directory($mockedClient);
+        $directory = new Directory($mockedClient);
 
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
-        self::assertTrue($directoryResource->rename($lib, 'test_dir', 'test_dir_renamed'));
+        self::assertTrue($directory->rename($library, 'test_dir', 'test_dir_renamed'));
     }
 
     /**
      * Test remove(), with invalid directory name
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testRemoveInvalidDirectoryName()
+    public function testRemoveInvalidDirectoryName(): void
     {
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
-        $directoryResource = new Directory(new SeafileHttpClient());
-        self::assertFalse($directoryResource->remove($lib, ''));
+        $directory = new Directory(new SeafileHttpClient());
+        self::assertFalse($directory->remove($library, ''));
     }
 
     /**
      * Test remove()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testRemove()
+    public function testRemove(): void
     {
         $getAllResponse = new Response(
             200,
@@ -419,11 +402,11 @@ function ($method, $uri, $params) use ($getAllResponse, $mkdirResponse, $expectU
                 }
             ));
 
-        $directoryResource = new Directory($mockedClient);
+        $directory = new Directory($mockedClient);
 
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
-        self::assertTrue($directoryResource->remove($lib, 'test_dir'));
+        self::assertTrue($directory->remove($library, 'test_dir'));
     }
 }
diff --git a/test/unit/Resource/FileTest.php b/test/unit/Resource/FileTest.php
index 3245161..3b5de33 100644
--- a/test/unit/Resource/FileTest.php
+++ b/test/unit/Resource/FileTest.php
@@ -31,16 +31,15 @@ class FileTest extends UnitTestCase
     /**
      * Test getDownloadUrl()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testGetDownloadUrl()
+    public function testGetDownloadUrl(): void
     {
-        $fileResource = new File($this->getMockedClient(
+        $file = new File($this->getMockedClient(
             new Response(200, ['Content-Type' => 'application/json'], '"https://some.example.com/some/url"')
         ));
 
-        $downloadLink = $fileResource->getDownloadUrl(new Library(), new DirectoryItem());
+        $downloadLink = $file->getDownloadUrl(new Library(), new DirectoryItem());
 
         // encapsulating quotes must be gone
         self::assertSame('https://some.example.com/some/url', $downloadLink);
@@ -48,8 +47,6 @@ public function testGetDownloadUrl()
 
     /**
      * Data provider for testUrlEncodePath()
-     *
-     * @return array
      */
     public static function dataProviderTestUrlEncodePath(): array
     {
@@ -69,18 +66,17 @@ public static function dataProviderTestUrlEncodePath(): array
      * @param string $path Path to encode
      * @param string $expectEncodedPath Expected encoded path
      *
-     * @return void
      * @dataProvider dataProviderTestUrlEncodePath
      * @throws ReflectionException
      */
-    public function testUrlEncodePath(string $path, string $expectEncodedPath)
+    public function testUrlEncodePath(string $path, string $expectEncodedPath): void
     {
-        $fileResource = $this->getMockBuilder(File::class)
+        $mock = $this->getMockBuilder(File::class)
             ->disableOriginalConstructor()
             ->addMethods([])
             ->getMock();
 
-        $actualEncodedPath = $this->invokeMethod($fileResource, 'urlencodePath', [$path]);
+        $actualEncodedPath = $this->invokeMethod($mock, 'urlencodePath', [$path]);
 
         self::assertSame($expectEncodedPath, $actualEncodedPath);
     }
@@ -88,16 +84,15 @@ public function testUrlEncodePath(string $path, string $expectEncodedPath)
     /**
      * Test getUploadUrl()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testGetUploadLink()
+    public function testGetUploadLink(): void
     {
-        $fileResource = new File($this->getMockedClient(
+        $file = new File($this->getMockedClient(
             new Response(200, ['Content-Type' => 'application/json'], '"https://some.example.com/some/url"')
         ));
 
-        $uploadUrl = $fileResource->getUploadUrl(new Library());
+        $uploadUrl = $file->getUploadUrl(new Library());
 
         // encapsulating quotes must be gone
         self::assertSame('https://some.example.com/some/url', $uploadUrl);
@@ -107,11 +102,10 @@ public function testGetUploadLink()
      * Test getUploadUrl() with subdirectory. Expect the mocked client's `request` gets called with the parent_dir
      * parameter "p".
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testGetUploadLinkWithSubDirectory()
+    public function testGetUploadLinkWithSubDirectory(): void
     {
         $libId = "lib_id";
         $uploadDir = "/Somedir";
@@ -128,11 +122,11 @@ public function testGetUploadLinkWithSubDirectory()
                 self::equalTo('http://example.com/index.html/api' . File::API_VERSION . '/repos/' . $libId . '/upload-link/?p=' . $uploadDir)
             );
 
-        $fileResource = new File($mockedClient);
+        $file = new File($mockedClient);
 
-        $lib = new Library(['id' => $libId]);
+        $library = new Library(['id' => $libId]);
 
-        $uploadUrl = $fileResource->getUploadUrl($lib, true, $uploadDir);
+        $uploadUrl = $file->getUploadUrl($library, true, $uploadDir);
 
         self::assertSame('https://some.example.com/some/url', $uploadUrl);
     }
@@ -140,17 +134,16 @@ public function testGetUploadLinkWithSubDirectory()
     /**
      * Download a file, local destination path is already occupied
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testDownloadFromDirFileExists()
+    public function testDownloadFromDirFileExists(): void
     {
         $newFilename = tempnam($GLOBALS['BUILD_TMP'], uniqid());
-        $fileResource = new File($this->getMockedClient(new Response()));
+        $file = new File($this->getMockedClient(new Response()));
 
         try {
             $this->expectException('Exception');
-            $fileResource->downloadFromDir(new Library(), new DirectoryItem(), $newFilename, '/');
+            $file->downloadFromDir(new Library(), new DirectoryItem(), $newFilename, '/');
             $this->fail('Exception expected');
         } finally {
             unlink($newFilename);
@@ -160,29 +153,27 @@ public function testDownloadFromDirFileExists()
     /**
      * Try to upload a non-existent local file
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testUploadDoesNotExist()
+    public function testUploadDoesNotExist(): void
     {
         $filename = uniqid();
-        $fileResource = new File($this->getMockedClient(new Response()));
+        $file = new File($this->getMockedClient(new Response()));
 
         $this->expectException('Exception');
-        $fileResource->upload(new Library(), $filename);
+        $file->upload(new Library(), $filename);
         $this->fail('Exception expected');
     }
 
     /**
      * Test downloadFromDir()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testDownloadFromDir()
+    public function testDownloadFromDir(): void
     {
-        $fileResource = new FileResourceStub($this->getMockedClient(new Response()));
-        $response = $fileResource->downloadFromDir(new Library(), new DirectoryItem(), '/some/path', '/', 1);
+        $fileResourceStub = new FileResourceStub($this->getMockedClient(new Response()));
+        $response = $fileResourceStub->downloadFromDir(new Library(), new DirectoryItem(), '/some/path', '/', 1);
 
         self::assertInstanceOf(Response::class, $response);
     }
@@ -190,13 +181,12 @@ public function testDownloadFromDir()
     /**
      * Test download()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testDownload()
+    public function testDownload(): void
     {
-        $fileResource = new FileResourceStub($this->getMockedClient(new Response()));
-        $response = $fileResource->download(new Library(), '/some/path', '/some/file', 1);
+        $fileResourceStub = new FileResourceStub($this->getMockedClient(new Response()));
+        $response = $fileResourceStub->download(new Library(), '/some/path', '/some/file', 1);
 
         // @todo Assert request query params
         self::assertInstanceOf(Response::class, $response);
@@ -205,13 +195,12 @@ public function testDownload()
     /**
      * Test upload()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testUpload()
+    public function testUpload(): void
     {
-        $fileResource = new FileResourceStub($this->getMockedClient(new Response()));
-        $response = $fileResource->upload(new Library(), $GLOBALS['BUILD_TMP'], '/');
+        $fileResourceStub = new FileResourceStub($this->getMockedClient(new Response()));
+        $response = $fileResourceStub->upload(new Library(), $GLOBALS['BUILD_TMP'], '/');
 
         self::assertInstanceOf(Response::class, $response);
     }
@@ -219,13 +208,12 @@ public function testUpload()
     /**
      * Test update()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testUpdate()
+    public function testUpdate(): void
     {
-        $fileResource = new FileResourceStub($this->getMockedClient(new Response()));
-        $response = $fileResource->update(new Library(), $GLOBALS['BUILD_TMP'], '/');
+        $fileResourceStub = new FileResourceStub($this->getMockedClient(new Response()));
+        $response = $fileResourceStub->update(new Library(), $GLOBALS['BUILD_TMP'], '/');
 
         self::assertInstanceOf(Response::class, $response);
     }
@@ -233,53 +221,50 @@ public function testUpdate()
     /**
      * test getFileDetail()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testGetFileDetail()
+    public function testGetFileDetail(): void
     {
-        $fileResource = new File($this->getMockedClient(new Response(
+        $file = new File($this->getMockedClient(new Response(
             200,
             ['Content-Type' => 'application/json'],
             '{"id": "cd8ec413c72388149911c84b046642da2ca4b935", "mtime": 1444760758, "type": "file", ' .
             '"name": "Seafile-PHP-SDK_Test_Upload_jt64pq.txt", "size": 32}'
         )));
 
-        $response = $fileResource->getFileDetail(new Library(), '/Seafile-PHP-SDK_Test_Upload_jt64pq.txt');
+        $directoryItem = $file->getFileDetail(new Library(), '/Seafile-PHP-SDK_Test_Upload_jt64pq.txt');
 
-        self::assertInstanceOf(DirectoryItem::class, $response);
-        self::assertInstanceOf(DateTime::class, $response->mtime);
-        self::assertSame('Seafile-PHP-SDK_Test_Upload_jt64pq.txt', $response->name);
-        self::assertSame('file', $response->type);
-        self::assertequals('32', $response->size);
+        self::assertInstanceOf(DirectoryItem::class, $directoryItem);
+        self::assertInstanceOf(DateTime::class, $directoryItem->mtime);
+        self::assertSame('Seafile-PHP-SDK_Test_Upload_jt64pq.txt', $directoryItem->name);
+        self::assertSame('file', $directoryItem->type);
+        self::assertequals('32', $directoryItem->size);
     }
 
     /**
      * Test getMultiPartParams() for update
-     *
-     * @return void
      */
-    public function testUpdateMultiPartParams()
+    public function testUpdateMultiPartParams(): void
     {
         $localFilePath = $GLOBALS['BUILD_TMP'] . '/' . uniqid('test_', true) . '.txt';
         file_put_contents($localFilePath, '0');
 
         try {
             $dir = '/';
-            $fileResource = new FileResourceStub($this->getMockedClient(new Response()));
+            $fileResourceStub = new FileResourceStub($this->getMockedClient(new Response()));
             self::assertContains(
                 [
                     'name' => 'parent_dir',
                     'contents' => $dir,
                 ],
-                $fileResource->getMultiPartParams($localFilePath, $dir, true)
+                $fileResourceStub->getMultiPartParams($localFilePath, $dir, true)
             );
             self::assertNotContains(
                 [
                     'name' => 'target_file',
                     'contents' => $dir . basename($localFilePath),
                 ],
-                $fileResource->getMultiPartParams($localFilePath, $dir, true)
+                $fileResourceStub->getMultiPartParams($localFilePath, $dir, true)
             );
         } finally {
             if (is_writable($localFilePath)) {
@@ -290,18 +275,16 @@ public function testUpdateMultiPartParams()
 
     /**
      * Test getMultiPartParams() with new file name
-     *
-     * @return void
      */
-    public function testUpdateMultiPartParamsNewFilename()
+    public function testUpdateMultiPartParamsNewFilename(): void
     {
         $dir = '/';
         $localFilePath = $GLOBALS['BUILD_TMP'] . '/' . uniqid('test_', true) . '.txt';
-        $fileResource = new File($this->getMockedClient(new Response()));
+        $file = new File($this->getMockedClient(new Response()));
         $newFilename = $GLOBALS['BUILD_TMP'] . '/' . uniqid('test_', true) . '.txt';
         file_put_contents($localFilePath, 'abc');
 
-        $params = $fileResource->getMultiPartParams($localFilePath, $dir, true, $newFilename);
+        $params = $file->getMultiPartParams($localFilePath, $dir, true, $newFilename);
 
         $params[0]['contents'] = get_resource_type($params[0]['contents']);
 
@@ -331,30 +314,28 @@ public function testUpdateMultiPartParamsNewFilename()
 
     /**
      * Test getMultiPartParams() for upload
-     *
-     * @return void
      */
-    public function testUploadMultiPartParams()
+    public function testUploadMultiPartParams(): void
     {
         $localFilePath = $GLOBALS['BUILD_TMP'] . '/' . uniqid('test_', true) . '.txt';
         file_put_contents($localFilePath, '0');
 
         try {
             $dir = '/';
-            $fileResource = new FileResourceStub($this->getMockedClient(new Response()));
+            $fileResourceStub = new FileResourceStub($this->getMockedClient(new Response()));
             self::assertNotContains(
                 [
                     'name' => 'parent_dir',
                     'contents' => $dir,
                 ],
-                $fileResource->getMultiPartParams($localFilePath, $dir, false)
+                $fileResourceStub->getMultiPartParams($localFilePath, $dir, false)
             );
             self::assertContains(
                 [
                     'name' => 'target_file',
                     'contents' => $dir . basename($localFilePath),
                 ],
-                $fileResource->getMultiPartParams($localFilePath, $dir, false)
+                $fileResourceStub->getMultiPartParams($localFilePath, $dir, false)
             );
         } finally {
             if (is_writable($localFilePath)) {
@@ -366,26 +347,23 @@ public function testUploadMultiPartParams()
     /**
      * Test remove() with invalid file name
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testRemoveInvalidFilename()
+    public function testRemoveInvalidFilename(): void
     {
         /** @var SeafileHttpClient|MockObject $mockedClient */
         $mockedClient = $this->getMockBuilder(SeafileHttpClient::class)->getMock();
 
-        $fileResource = new File($mockedClient);
+        $file = new File($mockedClient);
 
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
-        self::assertFalse($fileResource->remove($lib, ''));
+        self::assertFalse($file->remove($library, ''));
     }
 
     /**
      * Data provider for testRenameInvalidFilename()
-     *
-     * @return array
      */
     public static function dataProviderTestRenameInvalidFilename(): array
     {
@@ -403,32 +381,29 @@ public static function dataProviderTestRenameInvalidFilename(): array
      * @param string $invalidFilePath Invalid file path
      * @param string $invalidNewFilename Invalid new file name
      *
-     * @return void
      * @dataProvider dataProviderTestRenameInvalidFilename
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testRenameInvalidFilename(string $invalidFilePath, string $invalidNewFilename)
+    public function testRenameInvalidFilename(string $invalidFilePath, string $invalidNewFilename): void
     {
         self::expectException('\InvalidArgumentException');
 
         /** @var SeafileHttpClient|MockObject $mockedClient */
         $mockedClient = $this->getMockBuilder(SeafileHttpClient::class)->getMock();
 
-        $fileResource = new File($mockedClient);
+        $file = new File($mockedClient);
 
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
-        $dirItem = new DirectoryItem(['dir' => $invalidFilePath]);
+        $directoryItem = new DirectoryItem(['dir' => $invalidFilePath]);
 
-        $fileResource->rename($lib, $dirItem, $invalidNewFilename);
+        $file->rename($library, $directoryItem, $invalidNewFilename);
     }
 
     /**
      * Data provider for testCopyInvalid()
-     *
-     * @return array
      */
     public static function dataProviderCopyInvalid(): array
     {
@@ -451,15 +426,14 @@ public static function dataProviderCopyInvalid(): array
      *
      * @param array $data Test data
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testCopyInvalid(array $data)
+    public function testCopyInvalid(array $data): void
     {
         /** @var SeafileHttpClient|MockObject $mockedClient */
         $mockedClient = $this->getMockBuilder(SeafileHttpClient::class)->getMock();
 
-        $fileResource = new File($mockedClient);
+        $file = new File($mockedClient);
 
         $srcLib = $data[0];
         $srcFilePath = $data[1];
@@ -467,16 +441,15 @@ public function testCopyInvalid(array $data)
         $dstFilePath = $data[3];
         $expected = $data[4];
 
-        self::assertSame($expected, $fileResource->copy($srcLib, $srcFilePath, $dstLib, $dstFilePath));
+        self::assertSame($expected, $file->copy($srcLib, $srcFilePath, $dstLib, $dstFilePath));
     }
 
     /**
      * Test remove()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testRemove()
+    public function testRemove(): void
     {
         $getAllResponse = new Response(
             200,
@@ -517,22 +490,21 @@ function ($method, $uri, $params) use ($getAllResponse, $deleteResponse, $expect
                 }
             ));
 
-        $fileResource = new File($mockedClient);
+        $file = new File($mockedClient);
 
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
-        self::assertTrue($fileResource->remove($lib, 'test_dir'));
+        self::assertTrue($file->remove($library, 'test_dir'));
     }
 
     /**
      * Test rename()
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testRename()
+    public function testRename(): void
     {
         new Response(
             200,
@@ -576,18 +548,16 @@ function ($method, $uri, $params) use ($renameResponse, $expectUri, $expectParam
                 }
             ));
 
-        $fileResource = new File($mockedClient);
+        $file = new File($mockedClient);
 
-        $lib = new Library(['id' => 'some-crazy-id']);
-        $dirItem = new DirectoryItem(['name' => 'test_file']);
+        $library = new Library(['id' => 'some-crazy-id']);
+        $directoryItem = new DirectoryItem(['name' => 'test_file']);
 
-        self::assertTrue($fileResource->rename($lib, $dirItem, $newFilename));
+        self::assertTrue($file->rename($library, $directoryItem, $newFilename));
     }
 
     /**
      * Data provider for testCopy() and testMove()
-     *
-     * @return array
      */
     public static function dataProviderCopyMove(): array
     {
@@ -603,10 +573,8 @@ public static function dataProviderCopyMove(): array
      * @dataProvider dataProviderCopyMove
      *
      * @param array $data Data provided
-     *
-     * @return void
      */
-    public function testCopyMove(array $data)
+    public function testCopyMove(array $data): void
     {
         $sourceLib = new Library();
         $sourceLib->id = 'some-crazy-id';
@@ -670,26 +638,25 @@ function ($method, $uri, $params) use ($getAllResponse, $response, $expectUri, $
                 }
             ));
 
-        $fileResource = new File($mockedClient);
+        $file = new File($mockedClient);
 
-        self::assertTrue($fileResource->{$data['operation']}($sourceLib, $srcPath, $destLib, $dstPath));
+        self::assertTrue($file->{$data['operation']}($sourceLib, $srcPath, $destLib, $dstPath));
     }
 
     /**
      * Test move() with invalid destination dir
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testMoveInvalidDestination()
+    public function testMoveInvalidDestination(): void
     {
         /** @var SeafileHttpClient|MockObject $mockedClient */
         $mockedClient = $this->getMockBuilder(SeafileHttpClient::class)->getMock();
 
-        $fileResource = new File($mockedClient);
+        $file = new File($mockedClient);
 
         self::assertFalse(
-            $fileResource->move(
+            $file->move(
                 new Library(),
                 '',
                 new Library(),
@@ -701,26 +668,25 @@ public function testMoveInvalidDestination()
     /**
      * Test getFileRevisionDownloadUrl()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testGetFileRevisionDownloadUrl()
+    public function testGetFileRevisionDownloadUrl(): void
     {
-        $fileResource = new File($this->getMockedClient(
+        $file = new File($this->getMockedClient(
             new Response(200, ['Content-Type' => 'application/json'], '"https://some.example.com/some/url"')
         ));
 
         $library = new Library();
         $library->id = 123;
 
-        $dirItem = new DirectoryItem();
-        $dirItem->path = '/';
-        $dirItem->name = 'some_test.txt';
+        $directoryItem = new DirectoryItem();
+        $directoryItem->path = '/';
+        $directoryItem->name = 'some_test.txt';
 
         $fileHistoryItem = new FileHistoryItem();
         $fileHistoryItem->id = 345;
 
-        $downloadUrl = $fileResource->getFileRevisionDownloadUrl($library, $dirItem, $fileHistoryItem);
+        $downloadUrl = $file->getFileRevisionDownloadUrl($library, $directoryItem, $fileHistoryItem);
 
         // encapsulating quotes must be gone
         self::assertSame('https://some.example.com/some/url', $downloadUrl);
@@ -731,23 +697,22 @@ public function testGetFileRevisionDownloadUrl()
     /**
      * Test downloadRevision()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testDownloadRevision()
+    public function testDownloadRevision(): void
     {
         $library = new Library();
         $library->id = 123;
 
-        $dirItem = new DirectoryItem();
-        $dirItem->path = '/';
-        $dirItem->name = 'some_test.txt';
+        $directoryItem = new DirectoryItem();
+        $directoryItem->path = '/';
+        $directoryItem->name = 'some_test.txt';
 
         $fileHistoryItem = new FileHistoryItem();
         $fileHistoryItem->id = 345;
 
-        $fileResource = new FileResourceStub($this->getMockedClient(new Response()));
-        $response = $fileResource->downloadRevision($library, $dirItem, $fileHistoryItem, '/tmp/yo.txt');
+        $fileResourceStub = new FileResourceStub($this->getMockedClient(new Response()));
+        $response = $fileResourceStub->downloadRevision($library, $directoryItem, $fileHistoryItem, '/tmp/yo.txt');
 
         self::assertInstanceOf(Response::class, $response);
 
@@ -757,12 +722,11 @@ public function testDownloadRevision()
     /**
      * Test getHistory()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testGetHistory()
+    public function testGetHistory(): void
     {
-        $fileResource = new File($this->getMockedClient(
+        $file = new File($this->getMockedClient(
             new Response(
                 200,
                 ['Content-Type' => 'application/json'],
@@ -770,10 +734,10 @@ public function testGetHistory()
             )
         ));
 
-        $lib = new Library();
-        $lib->id = 123;
+        $library = new Library();
+        $library->id = 123;
 
-        $fileHistoryItems = $fileResource->getHistory($lib, new DirectoryItem());
+        $fileHistoryItems = $file->getHistory($library, new DirectoryItem());
 
         self::assertIsArray($fileHistoryItems);
 
@@ -785,23 +749,21 @@ public function testGetHistory()
     /**
      * Test create() with invalid DirectoryItem
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testCreateInvalid()
+    public function testCreateInvalid(): void
     {
-        $fileResource = new File($this->getMockedClient(new Response()));
+        $file = new File($this->getMockedClient(new Response()));
 
-        self::assertFalse($fileResource->create(new Library, new DirectoryItem));
+        self::assertFalse($file->create(new Library, new DirectoryItem));
     }
 
     /**
      * Test create() with valid DirectoryItem
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testCreate()
+    public function testCreate(): void
     {
         $clientMock = $this->getMockedClient(
             new Response(
@@ -824,15 +786,15 @@ public function testCreate()
                 'success'
             )));
 
-        $fileResource = new File($clientMock);
+        $file = new File($clientMock);
 
-        $lib = new Library;
-        $lib->id = 123;
+        $library = new Library;
+        $library->id = 123;
 
-        $dirItem = new DirectoryItem;
-        $dirItem->path = '/';
-        $dirItem->name = 'some_name.txt';
+        $directoryItem = new DirectoryItem;
+        $directoryItem->path = '/';
+        $directoryItem->name = 'some_name.txt';
 
-        self::assertTrue($fileResource->create($lib, $dirItem));
+        self::assertTrue($file->create($library, $directoryItem));
     }
 }
diff --git a/test/unit/Resource/GroupTest.php b/test/unit/Resource/GroupTest.php
index 02986dc..f1403cc 100644
--- a/test/unit/Resource/GroupTest.php
+++ b/test/unit/Resource/GroupTest.php
@@ -23,10 +23,9 @@ class GroupTest extends UnitTestCase
     /**
      * Test getAll()
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testGetAll()
+    public function testGetAll(): void
     {
         $groupResource = new Group($this->getMockedClient(
             new Response(
diff --git a/test/unit/Resource/LibraryTest.php b/test/unit/Resource/LibraryTest.php
index 12ff84e..04cefae 100644
--- a/test/unit/Resource/LibraryTest.php
+++ b/test/unit/Resource/LibraryTest.php
@@ -27,12 +27,11 @@ class LibraryTest extends UnitTestCase
     /**
      * Test getAll()
      *
-     * @return void
      * @throws Exception
      */
-    public function testGetAll()
+    public function testGetAll(): void
     {
-        $libraryResource = new Library($this->getMockedClient(
+        $library = new Library($this->getMockedClient(
             new Response(
                 200,
                 ['Content-Type' => 'application/json'],
@@ -40,7 +39,7 @@ public function testGetAll()
             )
         ));
 
-        $libs = $libraryResource->getAll();
+        $libs = $library->getAll();
 
         self::assertIsArray($libs);
 
@@ -52,12 +51,11 @@ public function testGetAll()
     /**
      * getById()
      *
-     * @return void
      * @throws Exception
      */
-    public function testGetById()
+    public function testGetById(): void
     {
-        $libraryResource = new Library($this->getMockedClient(
+        $library = new Library($this->getMockedClient(
             new Response(
                 200,
                 ['Content-Type' => 'application/json'],
@@ -65,16 +63,15 @@ public function testGetById()
             )
         ));
 
-        self::assertInstanceOf(LibraryType::class, $libraryResource->getById('some_id'));
+        self::assertInstanceOf(LibraryType::class, $library->getById('some_id'));
     }
 
     /**
      * Try to decrypt without query parameters. Must fail of course.
      *
-     * @return void
      * @throws Exception
      */
-    public function testDecryptMissingQuery()
+    public function testDecryptMissingQuery(): void
     {
         $library = new Library($this->getMockedClient(new Response));
         $this->expectException('Exception');
@@ -84,10 +81,9 @@ public function testDecryptMissingQuery()
     /**
      * Try to decrypt without password. Must fail of course.
      *
-     * @return void
      * @throws Exception
      */
-    public function testDecryptMissingPassword()
+    public function testDecryptMissingPassword(): void
     {
         $library = new Library($this->getMockedClient(new Response));
         $this->expectException('Exception');
@@ -97,10 +93,9 @@ public function testDecryptMissingPassword()
     /**
      * Decryption fails
      *
-     * @return void
      * @throws Exception
      */
-    public function testDecryptUnsuccessfully()
+    public function testDecryptUnsuccessfully(): void
     {
         $library = new Library($this->getMockedClient(
             new Response(
@@ -121,10 +116,9 @@ public function testDecryptUnsuccessfully()
     /**
      * Decryption succeeds
      *
-     * @return void
      * @throws Exception
      */
-    public function testDecryptSuccessfully()
+    public function testDecryptSuccessfully(): void
     {
         $library = new Library($this->getMockedClient(
             new Response(
@@ -144,8 +138,6 @@ public function testDecryptSuccessfully()
 
     /**
      * Data provider for testExists()
-     *
-     * @return array
      */
     public static function dataProviderExists(): array
     {
@@ -164,12 +156,11 @@ public static function dataProviderExists(): array
      *
      * @param array $data Test data
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testExists(array $data)
+    public function testExists(array $data): void
     {
-        $libraryResource = new Library($this->getMockedClient(
+        $library = new Library($this->getMockedClient(
             new Response(
                 200,
                 ['Content-Type' => 'application/json'],
@@ -177,13 +168,11 @@ public function testExists(array $data)
             )
         ));
 
-        self::assertSame($data[2], $libraryResource->exists($data[0], $data[1]));
+        self::assertSame($data[2], $library->exists($data[0], $data[1]));
     }
 
     /**
      * DataProvider for testCreateInvalid()
-     *
-     * @return array
      */
     public static function dataProviderCreateInvalid(): array
     {
@@ -200,12 +189,11 @@ public static function dataProviderCreateInvalid(): array
      *
      * @param array $data Test data
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testCreateInvalid(array $data)
+    public function testCreateInvalid(array $data): void
     {
-        $libraryResource = new Library($this->getMockedClient(
+        $library = new Library($this->getMockedClient(
             new Response(
                 200,
                 ['Content-Type' => 'application/json'],
@@ -213,18 +201,17 @@ public function testCreateInvalid(array $data)
             )
         ));
 
-        self::assertSame($data[1], $libraryResource->create($data[0]));
+        self::assertSame($data[1], $library->create($data[0]));
     }
 
     /**
      * Test remove(), provide invalid parameters, expect failure
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testRemoveInvalid()
+    public function testRemoveInvalid(): void
     {
-        $libraryResource = new Library($this->getMockedClient(
+        $library = new Library($this->getMockedClient(
             new Response(
                 200,
                 ['Content-Type' => 'application/json'],
@@ -232,13 +219,11 @@ public function testRemoveInvalid()
             )
         ));
 
-        self::assertFalse($libraryResource->remove(''));
+        self::assertFalse($library->remove(''));
     }
 
     /**
      * DataProvider for create()
-     *
-     * @return array
      */
     public static function dataProviderCreate(): array
     {
@@ -257,10 +242,9 @@ public static function dataProviderCreate(): array
      *
      * @param array $data Test data
      *
-     * @return void
      * @throws GuzzleException
      */
-    public function testCreate(array $data)
+    public function testCreate(array $data): void
     {
         $getAllResponse = new Response(
             200,
@@ -333,11 +317,10 @@ function ($method, $uri, $params) use ($getAllResponse, $createResponse, $expect
     /**
      * Test remove()
      *
-     * @return void
      * @throws Exception
      * @throws GuzzleException
      */
-    public function testRemove()
+    public function testRemove(): void
     {
         $getAllResponse = new Response(
             200,
diff --git a/test/unit/Resource/MultiTest.php b/test/unit/Resource/MultiTest.php
index 1f6329d..a768bda 100644
--- a/test/unit/Resource/MultiTest.php
+++ b/test/unit/Resource/MultiTest.php
@@ -26,47 +26,43 @@ class MultiTest extends UnitTestCase
     /**
      * Test delete() with empty paths
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testDeleteEmpty()
+    public function testDeleteEmpty(): void
     {
         /** @var SeafileHttpClient|MockObject $mockedClient */
         $mockedClient = $this->getMockBuilder(SeafileHttpClient::class)->getMock();
 
-        $multiResource = new Multi($mockedClient);
+        $multi = new Multi($mockedClient);
 
-        $lib = new Library();
+        $library = new Library();
 
-        self::assertFalse($multiResource->delete($lib, []));
+        self::assertFalse($multi->delete($library, []));
     }
 
     /**
      * Test copy() and move() with empty paths
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testCopyMoveEmpty()
+    public function testCopyMoveEmpty(): void
     {
         /** @var SeafileHttpClient|MockObject $mockedClient */
         $mockedClient = $this->getMockBuilder(SeafileHttpClient::class)->getMock();
 
-        $multiResource = new Multi($mockedClient);
+        $multi = new Multi($mockedClient);
 
-        $lib = new Library();
+        $library = new Library();
 
         foreach (['copy', 'move'] as $operation) {
-            self::assertFalse($multiResource->{$operation}($lib, [], $lib, ''));
+            self::assertFalse($multi->{$operation}($library, [], $library, ''));
         }
     }
 
     /**
      * Data provider for testDelete()
-     *
-     * @return array
      */
     public static function dataProviderDelete(): array
     {
@@ -109,11 +105,10 @@ public static function dataProviderDelete(): array
      *
      * @param array $data DataProvider data
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testDelete(array $data)
+    public function testDelete(array $data): void
     {
         $getAllResponse = new Response(
             200,
@@ -163,18 +158,16 @@ function ($method, $uri, $params) use ($getAllResponse, $deleteResponse, $expect
                 }
             ));
 
-        $fileResource = new Multi($mockedClient);
+        $multi = new Multi($mockedClient);
 
-        $lib = new Library();
-        $lib->id = 'some-crazy-id';
+        $library = new Library();
+        $library->id = 'some-crazy-id';
 
-        self::assertSame($data['assert'], $fileResource->delete($lib, $deletePaths));
+        self::assertSame($data['assert'], $multi->delete($library, $deletePaths));
     }
 
     /**
      * Data provider for testCopyMove()
-     *
-     * @return array
      */
     public static function dataProviderCopyMove(): array
     {
@@ -249,11 +242,10 @@ public static function dataProviderCopyMove(): array
      *
      * @param array $data DataProvider data
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testCopyMove(array $data)
+    public function testCopyMove(array $data): void
     {
         $getAllResponse = new Response(
             200,
@@ -318,11 +310,11 @@ function ($method, $uri, $params) use ($getAllResponse, $deleteResponse, $expect
                 }
             ));
 
-        $fileResource = new Multi($mockedClient);
+        $multi = new Multi($mockedClient);
 
         self::assertSame(
             $data['assert'],
-            $fileResource->{$data['operation']}($srcLib, $filePaths, $dstLib, $destDir)
+            $multi->{$data['operation']}($srcLib, $filePaths, $dstLib, $destDir)
         );
     }
 }
diff --git a/test/unit/Resource/ResourceTest.php b/test/unit/Resource/ResourceTest.php
index 515efe7..4c66ccb 100644
--- a/test/unit/Resource/ResourceTest.php
+++ b/test/unit/Resource/ResourceTest.php
@@ -24,12 +24,10 @@ class ResourceTest extends UnitTestCase
 {
     /**
      * Test that clipUri() will consistently return URIs without trailing slash.
-     *
-     * @return void
      */
-    public function testClipUri()
+    public function testClipUri(): void
     {
-        $directoryResource = new Directory($this->getMockedClient(
+        $directory = new Directory($this->getMockedClient(
             new Response(200, ['Content-Type' => 'application/json'], '')
         ));
 
@@ -41,16 +39,14 @@ public function testClipUri()
         ];
 
         foreach ($uris as $uri => $clippedUri) {
-            self::assertSame($clippedUri, $directoryResource->clipUri($uri));
+            self::assertSame($clippedUri, $directory->clipUri($uri));
         }
     }
 
     /**
      * Test that getApiBaseUrl() returns the actual API base url depending on the resource.
-     *
-     * @return void
      */
-    public function testGetApiBaseUrl()
+    public function testGetApiBaseUrl(): void
     {
         /** @var Client|MockObject $mockedClient */
         $mockedClient = $this->getMockBuilder(Client::class)->getMock();
@@ -67,7 +63,7 @@ public function testGetApiBaseUrl()
             ->method('getConfig')
             ->willReturn('https://example.com/seafile');
 
-        $shareLinkResource = new ShareLinks($mockedClient);
-        self::assertSame('http://example.com/seafile/api/v2.1', $shareLinkResource->getApiBaseUrl());
+        $shareLinks = new ShareLinks($mockedClient);
+        self::assertSame('http://example.com/seafile/api/v2.1', $shareLinks->getApiBaseUrl());
     }
 }
diff --git a/test/unit/Resource/ShareLinksTest.php b/test/unit/Resource/ShareLinksTest.php
index 386a35d..e5d76d7 100644
--- a/test/unit/Resource/ShareLinksTest.php
+++ b/test/unit/Resource/ShareLinksTest.php
@@ -28,13 +28,12 @@ class ShareLinksTest extends UnitTestCase
     /**
      * Test getAll()
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testGetAll()
+    public function testGetAll(): void
     {
-        $sharedLinkResource = new ShareLinks($this->getMockedClient(
+        $shareLinks = new ShareLinks($this->getMockedClient(
             new Response(
                 200,
                 ['Content-Type' => 'application/json'],
@@ -42,7 +41,7 @@ public function testGetAll()
             )
         ));
 
-        $sharedLinks = $sharedLinkResource->getAll();
+        $sharedLinks = $shareLinks->getAll();
 
         self::assertIsArray($sharedLinks);
 
@@ -53,14 +52,13 @@ public function testGetAll()
 
     /**
      * Provide test data for remove()
-     * @return array
      */
     public static function dataProviderRemove(): array
     {
         // removeResponseCode, responseBody, expectedResult
         return [
-            [200, "{\"success\":true}", true], // test normal success case
-            [200, "{\"success\":false}", false], // test 'soft' error
+            [200, '{"success":true}', true], // test normal success case
+            [200, '{"success":false}', false], // test 'soft' error
             [500, "", false] // test 'hard' error
         ];
     }
@@ -70,14 +68,10 @@ public static function dataProviderRemove(): array
      *
      * @dataProvider dataProviderRemove
      *
-     * @param int $removeResponseCode
-     * @param string $responseBody
-     * @param bool $expectedResult
      *
-     * @return void
      * @throws Exception
      */
-    public function testRemove(int $removeResponseCode, string $responseBody, bool $expectedResult)
+    public function testRemove(int $removeResponseCode, string $responseBody, bool $expectedResult): void
     {
         $removeResponse = new Response(
             $removeResponseCode,
@@ -94,19 +88,17 @@ public function testRemove(int $removeResponseCode, string $responseBody, bool $
             ->method('request')
             ->willReturn($removeResponse);
 
-        $shareLinksResource = new ShareLinks($mockedClient);
+        $shareLinks = new ShareLinks($mockedClient);
 
         $sharedLink = new SharedLink();
         $sharedLink->url = 'https://seafile.example.com/f/abc/';
         $sharedLink->token = 'some_token';
 
-        self::assertSame($expectedResult, $shareLinksResource->remove($sharedLink));
+        self::assertSame($expectedResult, $shareLinks->remove($sharedLink));
     }
 
     /**
      * DataProvider for create()
-     *
-     * @return array
      */
     public static function dataProviderCreate(): array
     {
@@ -114,7 +106,7 @@ public static function dataProviderCreate(): array
         return [
             [ // test normal successful case
                 200,
-                'Seafile\Client\Type\SharedLink',
+                SharedLink::class,
                 file_get_contents(__DIR__ . '/../../assets/ShareLinksTest_create.json')
             ],
             [ // test error handling
@@ -135,13 +127,9 @@ public static function dataProviderCreate(): array
      *
      * @dataProvider dataProviderCreate
      *
-     * @param int $createResponseCode
-     * @param string|null $returnType
-     * @param string $responseBody
-     * @return void
      * @throws Exception
      */
-    public function testCreate(int $createResponseCode, ?string $returnType, string $responseBody)
+    public function testCreate(int $createResponseCode, ?string $returnType, string $responseBody): void
     {
         $headers = [
             'Content-Type' => 'application/json',
@@ -162,24 +150,24 @@ public function testCreate(int $createResponseCode, ?string $returnType, string
             ->with('base_uri')
             ->willReturn('http://example.com');
 
-        $sharedLinkResource = new ShareLinks($mockedClient);
+        $shareLinks = new ShareLinks($mockedClient);
 
-        $sharedLinkType = new SharedLink();
-        $sharedLinkType->url = 'https://seafile.example.com/f/abc/';
+        $sharedLink = new SharedLink();
+        $sharedLink->url = 'https://seafile.example.com/f/abc/';
 
-        $libraryType = new LibraryType();
-        $libraryType->id = 'decaf-deadbeef-dad';
+        $library = new LibraryType();
+        $library->id = 'decaf-deadbeef-dad';
 
-        $permissions = new SharedLinkPermissions(SharedLinkPermissions::CAN_DOWNLOAD);
+        $sharedLinkPermissions = new SharedLinkPermissions(SharedLinkPermissions::CAN_DOWNLOAD);
 
         if (is_null($returnType)) {
             self::assertNull(
-                $sharedLinkResource->create($libraryType, '/abc', $permissions, 123, 'pa55word')
+                $shareLinks->create($library, '/abc', $sharedLinkPermissions, 123, 'pa55word')
             );
         } else {
             self::assertInstanceOf(
                 $returnType,
-                $sharedLinkResource->create($libraryType, '/abc', $permissions, 123, 'pa55word')
+                $shareLinks->create($library, '/abc', $sharedLinkPermissions, 123, 'pa55word')
             );
         }
     }
diff --git a/test/unit/Resource/StarredFileTest.php b/test/unit/Resource/StarredFileTest.php
index d7a7ac4..ebda192 100644
--- a/test/unit/Resource/StarredFileTest.php
+++ b/test/unit/Resource/StarredFileTest.php
@@ -27,13 +27,12 @@ class StarredFileTest extends UnitTestCase
     /**
      * Test getAll()
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testGetAll()
+    public function testGetAll(): void
     {
-        $starredFileResource = new StarredFile($this->getMockedClient(
+        $starredFile = new StarredFile($this->getMockedClient(
             new Response(
                 200,
                 ['Content-Type' => 'application/json'],
@@ -41,7 +40,7 @@ public function testGetAll()
             )
         ));
 
-        $starredDirItems = $starredFileResource->getAll();
+        $starredDirItems = $starredFile->getAll();
 
         self::assertIsArray($starredDirItems);
 
@@ -53,35 +52,33 @@ public function testGetAll()
     /**
      * Test star() with wrong DirItem type
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testStarWrongType()
+    public function testStarWrongType(): void
     {
-        $starredFileResource = new StarredFile($this->getMockedClient(new Response()));
+        $starredFile = new StarredFile($this->getMockedClient(new Response()));
 
         $this->expectException('Exception');
         $this->expectExceptionMessage('Cannot star other items than files.');
 
-        $starredFileResource->star(new LibraryType(), new DirectoryItem());
+        $starredFile->star(new LibraryType(), new DirectoryItem());
     }
 
     /**
      * Test star()
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testStar()
+    public function testStar(): void
     {
-        $lib = new LibraryType();
-        $lib->id = 123;
+        $library = new LibraryType();
+        $library->id = 123;
 
-        $dirItem = new DirectoryItem();
-        $dirItem->type = 'file';
-        $dirItem->path = '/some/path';
+        $directoryItem = new DirectoryItem();
+        $directoryItem->type = 'file';
+        $directoryItem->path = '/some/path';
 
         $responseUrl = 'https://example.com/test/';
 
@@ -108,7 +105,7 @@ public function testStar()
             )
             // Return what was passed to offsetGet as a new instance
             ->will(self::returnCallback(
-                function ($method, $uri, $params) use ($starResponse, $lib, $dirItem) {
+                function ($method, $uri, array $params) use ($starResponse, $library, $directoryItem): Response|\Response {
 
                     $hasParams = array_key_exists('headers', $params)
                         && array_key_exists('multipart', $params)
@@ -117,8 +114,8 @@ function ($method, $uri, $params) use ($starResponse, $lib, $dirItem) {
                         && array_key_exists('name', $params['multipart'][1])
                         && array_key_exists('contents', $params['multipart'][1]);
 
-                    $hasContents = $params['multipart'][0]['contents'] === $lib->id
-                        && $params['multipart'][1]['contents'] === $dirItem->path;
+                    $hasContents = $params['multipart'][0]['contents'] === $library->id
+                        && $params['multipart'][1]['contents'] === $directoryItem->path;
 
                     if ($hasParams
                         && $hasContents
@@ -132,9 +129,9 @@ function ($method, $uri, $params) use ($starResponse, $lib, $dirItem) {
                 }
             ));
 
-        $starredFileResource = new StarredFile($mockedClient);
+        $starredFile = new StarredFile($mockedClient);
 
-        $result = $starredFileResource->star($lib, $dirItem);
+        $result = $starredFile->star($library, $directoryItem);
 
         self::assertSame($responseUrl, $result);
     }
@@ -142,18 +139,17 @@ function ($method, $uri, $params) use ($starResponse, $lib, $dirItem) {
     /**
      * Test star() with error response
      *
-     * @return void
      * @throws Exception
      * @throws GuzzleException
      */
-    public function testStarErrorStatusCode()
+    public function testStarErrorStatusCode(): void
     {
-        $lib = new LibraryType();
-        $lib->id = 123;
+        $library = new LibraryType();
+        $library->id = 123;
 
-        $dirItem = new DirectoryItem();
-        $dirItem->type = 'file';
-        $dirItem->path = '/some/path';
+        $directoryItem = new DirectoryItem();
+        $directoryItem->type = 'file';
+        $directoryItem->path = '/some/path';
 
         $responseUrl = 'https://example.com/test/';
 
@@ -178,29 +174,28 @@ public function testStarErrorStatusCode()
             ->with('POST')
             ->willReturn($starResponse);
 
-        $starredFileResource = new StarredFile($mockedClient);
+        $starredFile = new StarredFile($mockedClient);
 
         $this->expectException('Exception');
         $this->expectExceptionMessage('Could not star file');
 
-        $starredFileResource->star($lib, $dirItem);
+        $starredFile->star($library, $directoryItem);
     }
 
     /**
      * Test star() with missing location
      *
-     * @return void
      * @throws Exception
      * @throws GuzzleException
      */
-    public function testStarErrorMissingLocation()
+    public function testStarErrorMissingLocation(): void
     {
-        $lib = new LibraryType();
-        $lib->id = 123;
+        $library = new LibraryType();
+        $library->id = 123;
 
-        $dirItem = new DirectoryItem();
-        $dirItem->type = 'file';
-        $dirItem->path = '/some/path';
+        $directoryItem = new DirectoryItem();
+        $directoryItem->type = 'file';
+        $directoryItem->path = '/some/path';
 
         /** @var SeafileHttpClient|MockObject $mockedClient */
         $mockedClient = $this->getMockBuilder(SeafileHttpClient::class)->getMock();
@@ -215,18 +210,16 @@ public function testStarErrorMissingLocation()
             ->with('POST')
             ->willReturn(new Response(500));
 
-        $starredFileResource = new StarredFile($mockedClient);
+        $starredFile = new StarredFile($mockedClient);
 
         $this->expectException('Exception');
         $this->expectExceptionMessage('Could not star file');
 
-        $starredFileResource->star($lib, $dirItem);
+        $starredFile->star($library, $directoryItem);
     }
 
     /**
      * DataProvider for unstar()
-     *
-     * @return array
      */
     public static function dataProviderUnstar(): array
     {
@@ -251,19 +244,18 @@ public static function dataProviderUnstar(): array
      *
      * @param array $data Data provider array
      *
-     * @return void
      * @throws GuzzleException
      * @throws Exception
      * @dataProvider dataProviderUnstar
      */
-    public function testUnstar(array $data)
+    public function testUnstar(array $data): void
     {
-        $lib = new LibraryType();
-        $lib->id = 123;
+        $library = new LibraryType();
+        $library->id = 123;
 
-        $dirItem = new DirectoryItem();
-        $dirItem->type = 'file';
-        $dirItem->path = '/some/path';
+        $directoryItem = new DirectoryItem();
+        $directoryItem->type = 'file';
+        $directoryItem->path = '/some/path';
 
         /** @var SeafileHttpClient|MockObject $mockedClient */
         $mockedClient = $this->getMockBuilder(SeafileHttpClient::class)->getMock();
@@ -280,11 +272,11 @@ public function testUnstar(array $data)
                 new Response($data['responseCode'])
             );
 
-        $starredFileResource = new StarredFile($mockedClient);
+        $starredFile = new StarredFile($mockedClient);
 
         self::assertSame(
             $data['result'],
-            $starredFileResource->unstar($lib, $dirItem)
+            $starredFile->unstar($library, $directoryItem)
         );
     }
 }
diff --git a/test/unit/Stubs/FileResourceStub.php b/test/unit/Stubs/FileResourceStub.php
index c26f2d9..794eb82 100644
--- a/test/unit/Stubs/FileResourceStub.php
+++ b/test/unit/Stubs/FileResourceStub.php
@@ -20,35 +20,27 @@ class FileResourceStub extends File
     /**
      * Get download URL of a file
      *
-     * @param LibraryType $library Library instance
-     * @param DirectoryItem $item Item instance
+     * @param LibraryType $libraryType Library instance
+     * @param DirectoryItem $directoryItem Item instance
      * @param string $dir Dir string
      * @param int $reuse Reuse more than once per hour
-     *
-     * @return string
      */
-    public function getDownloadUrl(LibraryType $library, DirectoryItem $item, string $dir = '/', int $reuse = 1)
+    public function getDownloadUrl(LibraryType $libraryType, DirectoryItem $directoryItem, string $dir = '/', int $reuse = 1): string
     {
-        $library = null;
-        $item = null;
-        $dir = null;
-        $reuse = null;
         return 'http://download.example.com/';
     }
 
     /**
      * Get upload URL
      *
-     * @param LibraryType $library Library instance
+     * @param LibraryType $libraryType Library instance
      * @param bool $newFile Is new file (=upload) or not (=update)
      * @param string $dir Directory to upload to
      *
      * @return String Upload link
      */
-    public function getUploadUrl(LibraryType $library, bool $newFile = true, string $dir = "/"): string
+    public function getUploadUrl(LibraryType $libraryType, bool $newFile = true, string $dir = "/"): string
     {
-        $library = null;
-        $newFile = null;
         return 'http://upload.example.com/';
     }
 }
diff --git a/test/unit/Type/DirectoryItemUnitTest.php b/test/unit/Type/DirectoryItemUnitTest.php
index c0b0b09..045dfe1 100644
--- a/test/unit/Type/DirectoryItemUnitTest.php
+++ b/test/unit/Type/DirectoryItemUnitTest.php
@@ -21,10 +21,8 @@ class DirectoryItemUnitTest extends UnitTestCase
 {
     /**
      * DataProvider for testFromArray()
-     *
-     * @return array
      */
-    public function dataFromArray()
+    public function dataFromArray(): array
     {
         return [
             // [[expect response code, expected result, password]]
@@ -48,18 +46,17 @@ public function dataFromArray()
      *
      * @param array $data Dataprovider array
      *
-     * @return void
      * @dataProvider dataFromArray
      * @throws GuzzleException
      * @throws Exception
      */
-    public function testFromArray(array $data)
+    public function testFromArray(array $data): void
     {
-        $dirItem = new DirectoryItem([
+        $directoryItem = new DirectoryItem([
             'dir' => $data['dir'],
         ]);
 
-        self::assertSame($data['dir'], $dirItem->dir);
-        self::assertSame($data['type'], $dirItem->type);
+        self::assertSame($data['dir'], $directoryItem->dir);
+        self::assertSame($data['type'], $directoryItem->type);
     }
 }
diff --git a/test/unit/Type/TypeUnitTest.php b/test/unit/Type/TypeUnitTest.php
index f1a726c..12a1e8c 100644
--- a/test/unit/Type/TypeUnitTest.php
+++ b/test/unit/Type/TypeUnitTest.php
@@ -26,33 +26,31 @@ class TypeUnitTest extends UnitTestCase
     /**
      * Test fromArray()
      *
-     * @return void
      * @throws Exception
      */
-    public function testFromArray()
+    public function testFromArray(): void
     {
-        $dirItem = new DirectoryItem([
+        $directoryItem = new DirectoryItem([
             'id' => 1,
             'size' => 2,
             'name' => 'my name',
             'type' => 'my type',
         ]);
 
-        self::assertSame(1, $dirItem->id);
-        self::assertSame(2, $dirItem->size);
-        self::assertSame('my name', $dirItem->name);
-        self::assertSame('my type', $dirItem->type);
+        self::assertSame(1, $directoryItem->id);
+        self::assertSame(2, $directoryItem->size);
+        self::assertSame('my name', $directoryItem->name);
+        self::assertSame('my type', $directoryItem->type);
     }
 
     /**
      * Test fromArray() with a non-existing property
      *
-     * @return void
      * @throws Exception
      */
-    public function testFromArrayPropertyMissing()
+    public function testFromArrayPropertyMissing(): void
     {
-        $dirItem = new DirectoryItem([
+        $directoryItem = new DirectoryItem([
             'id' => 1,
             'size' => 2,
             'name' => 'my name',
@@ -72,53 +70,49 @@ public function testFromArrayPropertyMissing()
                 'path' => null,
                 'repo' => null,
             ],
-            (array)$dirItem
+            (array)$directoryItem
         );
     }
 
     /**
      * Test fromArray() with create_time property
      *
-     * @return void
      * @throws Exception
      */
-    public function testFromArrayCreateTime()
+    public function testFromArrayCreateTime(): void
     {
-        $accountType = new AccountType([
+        $account = new AccountType([
             'create_time' => '1452202279000000',
         ]);
 
-        self::assertSame('2016-01-07T21:31:19+0000', $accountType->createTime->format(DateTime::ISO8601));
+        self::assertSame('2016-01-07T21:31:19+00:00', $account->createTime->format(\DateTimeInterface::ATOM));
     }
 
     /**
      * Test fromJson() with create_time property
      *
-     * @return void
      * @throws Exception
      */
-    public function testFromJsonCreateTime()
+    public function testFromJsonCreateTime(): void
     {
-        $accountType = new AccountType();
+        $account = new AccountType();
 
-        $accountType->fromJson(json_decode(json_encode([
+        $account->fromJson(json_decode(json_encode([
             'create_time' => '1452202279000000',
         ])));
 
-        self::assertSame('2016-01-07T21:31:19+0000', $accountType->createTime->format(DateTime::ISO8601));
+        self::assertSame('2016-01-07T21:31:19+00:00', $account->createTime->format(\DateTimeInterface::ATOM));
     }
 
     /**
      * Test toJson()
      *
-     * @return void
      * @throws Exception
      */
-    public function testJson()
+    public function testJson(): void
     {
-        $accountType = new AccountType();
-
-        $jsonString = $accountType->toJson();
+        $account = new AccountType();
+        $jsonString = $account->toJson();
 
         self::assertStringStartsWith('{"contactEmail":null', $jsonString);
         self::assertStringEndsWith('"total":null,"usage":null}', $jsonString);
@@ -126,8 +120,6 @@ public function testJson()
 
     /**
      * Data provider for testToArrayAssoc()
-     *
-     * @return array
      */
     public static function dataProviderTestToArrayAssoc(): array
     {
@@ -140,8 +132,8 @@ public static function dataProviderTestToArrayAssoc(): array
             ],
             [
                 [
-                    ['createTime' => 1452202279000000],
-                    ['createTime' => 1452202279000000] // no empty values
+                    ['create_time' => 1452202279000000],
+                    ['createTime' => DateTime::createFromFormat(\DateTimeInterface::ATOM, '2016-01-07T21:31:19+0000')] // no empty values
                 ],
             ],
         ];
@@ -152,22 +144,18 @@ public static function dataProviderTestToArrayAssoc(): array
      *
      * @param array $data Data provider array
      *
-     * @return void
      * @dataProvider dataProviderTestToArrayAssoc
      * @throws Exception
      */
-    public function testToArrayAssoc(array $data)
+    public function testToArrayAssoc(array $data): void
     {
         $accountType = (new AccountType())->fromArray($data[0]);
-
         self::assertEquals($data[1], $accountType->toArray());
     }
 
 
     /**
      * Data provider for testToArrayMultiPart()
-     *
-     * @return array
      */
     public static function dataProviderTestToArrayMultiPart(): array
     {
@@ -180,8 +168,8 @@ public static function dataProviderTestToArrayMultiPart(): array
             ],
             [
                 [
-                    ['createTime' => 1452202279000000],
-                    [['name' => 'create_time', 'contents' => '1452202279000000']] // no empty values
+                    ['create_time' => 1452202279000000],
+                    [['name' => 'create_time', 'contents' => '1452202279']] // no empty values
                 ],
             ],
         ];
@@ -192,11 +180,10 @@ public static function dataProviderTestToArrayMultiPart(): array
      *
      * @param array $data Data provider array
      *
-     * @return void
      * @dataProvider dataProviderTestToArrayMultiPart
      * @throws Exception
      */
-    public function testToArrayMultiPart(array $data)
+    public function testToArrayMultiPart(array $data): void
     {
         $accountType = (new AccountType())->fromArray($data[0]);
 
@@ -208,14 +195,13 @@ public function testToArrayMultiPart(array $data)
      *
      * Must yield AccountType instance
      *
-     * @return void
      * @throws Exception
      */
-    public function testFromArrayCreator()
+    public function testFromArrayCreator(): void
     {
         $email = 'someone@example.com';
         $groupType = (new GroupType())->fromArray(['creator' => $email]);
-        self::assertInstanceOf(Account::class, $groupType->creator);
+        self::assertInstanceOf(AccountType::class, $groupType->creator);
         self::assertSame($email, $groupType->creator->email);
     }
 }
diff --git a/test/unit/UnitTestCase.php b/test/unit/UnitTestCase.php
index 35dd5a2..6e4cacb 100644
--- a/test/unit/UnitTestCase.php
+++ b/test/unit/UnitTestCase.php
@@ -32,11 +32,11 @@ class UnitTestCase extends TestCase
      */
     public function invokeMethod(&$object, string $methodName, array $parameters = [])
     {
-        $reflection = new ReflectionClass(get_class($object));
-        $method = $reflection->getMethod($methodName);
-        $method->setAccessible(true);
+        $reflectionClass = new ReflectionClass($object::class);
+        $reflectionMethod = $reflectionClass->getMethod($methodName);
+        $reflectionMethod->setAccessible(true);
 
-        return $method->invokeArgs($object, $parameters);
+        return $reflectionMethod->invokeArgs($object, $parameters);
     }
 
     /**