diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5fab717..79fc560 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Added test for `PdfDocument::isLink()` function.
 - Reworked `putFonts` function of `PdfDocument` class.
 - Added test for `PdfEnumDefaultInterface`.
 - Removed covers class attribute.
diff --git a/composer.lock b/composer.lock
index eb8fc20..78f0183 100644
--- a/composer.lock
+++ b/composer.lock
@@ -1169,16 +1169,16 @@
         },
         {
             "name": "friendsofphp/php-cs-fixer",
-            "version": "v3.60.0",
+            "version": "v3.61.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/PHP-CS-Fixer/PHP-CS-Fixer.git",
-                "reference": "e595e4e070d17c5d42ed8c4206f630fcc5f401a4"
+                "reference": "737a24b6d531db9c034ac97524ac3a3bde0c20c0"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/PHP-CS-Fixer/PHP-CS-Fixer/zipball/e595e4e070d17c5d42ed8c4206f630fcc5f401a4",
-                "reference": "e595e4e070d17c5d42ed8c4206f630fcc5f401a4",
+                "url": "https://api.github.com/repos/PHP-CS-Fixer/PHP-CS-Fixer/zipball/737a24b6d531db9c034ac97524ac3a3bde0c20c0",
+                "reference": "737a24b6d531db9c034ac97524ac3a3bde0c20c0",
                 "shasum": ""
             },
             "require": {
@@ -1260,7 +1260,7 @@
             ],
             "support": {
                 "issues": "https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/issues",
-                "source": "https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/tree/v3.60.0"
+                "source": "https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/tree/v3.61.0"
             },
             "funding": [
                 {
@@ -1268,7 +1268,7 @@
                     "type": "github"
                 }
             ],
-            "time": "2024-07-25T09:26:51+00:00"
+            "time": "2024-07-31T08:18:16+00:00"
         },
         {
             "name": "myclabs/deep-copy",
@@ -2302,16 +2302,16 @@
         },
         {
             "name": "phpunit/phpunit",
-            "version": "11.2.8",
+            "version": "11.2.9",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/phpunit.git",
-                "reference": "a7a29e8d3113806f18f99d670f580a30e8ffff39"
+                "reference": "c197bbaaca360efda351369bf1fd9cc1ca6bcbf7"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/a7a29e8d3113806f18f99d670f580a30e8ffff39",
-                "reference": "a7a29e8d3113806f18f99d670f580a30e8ffff39",
+                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/c197bbaaca360efda351369bf1fd9cc1ca6bcbf7",
+                "reference": "c197bbaaca360efda351369bf1fd9cc1ca6bcbf7",
                 "shasum": ""
             },
             "require": {
@@ -2382,7 +2382,7 @@
             "support": {
                 "issues": "https://github.com/sebastianbergmann/phpunit/issues",
                 "security": "https://github.com/sebastianbergmann/phpunit/security/policy",
-                "source": "https://github.com/sebastianbergmann/phpunit/tree/11.2.8"
+                "source": "https://github.com/sebastianbergmann/phpunit/tree/11.2.9"
             },
             "funding": [
                 {
@@ -2398,7 +2398,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2024-07-18T14:56:37+00:00"
+            "time": "2024-07-30T11:09:23+00:00"
         },
         {
             "name": "psalm/plugin-phpunit",
diff --git a/tests/PdfDocPropertiesTest.php b/tests/PdfDocPropertiesTest.php
index 5ffba06..d413ea6 100644
--- a/tests/PdfDocPropertiesTest.php
+++ b/tests/PdfDocPropertiesTest.php
@@ -12,8 +12,21 @@
 
 namespace fpdf;
 
+use PHPUnit\Framework\Attributes\DataProvider;
+
 class PdfDocPropertiesTest extends AbstractPdfDocTestCase
 {
+    public static function getIsLinks(): \Generator
+    {
+        yield [null, false];
+        yield ['', false];
+        yield [0, false];
+        yield [-1, false];
+
+        yield ['link', true];
+        yield [1, true];
+    }
+
     public function testAddPageClosed(): void
     {
         self::expectException(PdfException::class);
@@ -144,6 +157,13 @@ public function testHttpEncode(): void
         $doc->output(PdfDestination::DOWNLOAD, '¢FAKE¢');
     }
 
+    #[DataProvider('getIsLinks')]
+    public function testIsLink(string|int|null $link, bool $expected): void
+    {
+        $actual = PdfDocument::isLink($link);
+        self::assertSame($expected, $actual);
+    }
+
     public function testLastHeight(): void
     {
         $doc = $this->createDocument();