feat: add ShouldHaveOnlyOnePublicMethod rule

docs/documentation/assertions.md

@@ -35,3 +35,6 @@ It asserts that the selected classes **do not use the constructor** of the targe
 It asserts that the selected classes **does not depend** on anything else than the target classes.
 
 This would be equivalent to `shouldNotDependOn()` with the negation of the target classes.
+
+## shouldHaveOnlyOnePublicMethod()
+It asserts that the selected classes **only have one public method**.

extension.neon

@@ -48,6 +48,12 @@ services:
 		tags:
 			- phpstan.rules.rule
 
+	# ShouldHaveOnlyOnePublicMethod rules
+	-
+		class: PHPat\Rule\Assertion\Declaration\ShouldHaveOnlyOnePublicMethod\HasOnlyOnePublicMethodRule
+		tags:
+			- phpstan.rules.rule
+
     # # # # # RELATION RULES # # # # #
 
 	# ShouldImplement rules

src/Rule/Assertion/Declaration/ShouldHaveOnlyOnePublicMethod/HasOnlyOnePublicMethodRule.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace PHPat\Rule\Assertion\Declaration\ShouldHaveOnlyOnePublicMethod;
+
+use PHPat\Rule\Extractor\Declaration\OnePublicMethodExtractor;
+
+class HasOnlyOnePublicMethodRule extends ShouldHaveOnlyOnePublicMethod
+{
+    use OnePublicMethodExtractor;
+}

src/Rule/Assertion/Declaration/ShouldHaveOnlyOnePublicMethod/ShouldHaveOnlyOnePublicMethod.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace PHPat\Rule\Assertion\Declaration\ShouldHaveOnlyOnePublicMethod;
+
+use PHPat\Configuration;
+use PHPat\Rule\Assertion\Declaration\DeclarationAssertion;
+use PHPat\Rule\Assertion\Declaration\ValidationTrait;
+use PHPat\Statement\Builder\StatementBuilderFactory;
+use PHPStan\Reflection\ClassReflection;
+use PHPStan\Reflection\ReflectionProvider;
+use PHPStan\Type\FileTypeMapper;
+
+abstract class ShouldHaveOnlyOnePublicMethod extends DeclarationAssertion
+{
+    use ValidationTrait;
+
+    public function __construct(
+        StatementBuilderFactory $statementBuilderFactory,
+        Configuration $configuration,
+        ReflectionProvider $reflectionProvider,
+        FileTypeMapper $fileTypeMapper
+    ) {
+        parent::__construct(
+            __CLASS__,
+            $statementBuilderFactory,
+            $configuration,
+            $reflectionProvider,
+            $fileTypeMapper
+        );
+    }
+
+    protected function applyValidation(string $ruleName, ClassReflection $subject, bool $meetsDeclaration, array $tips): array
+    {
+        return $this->applyShould($ruleName, $subject, $meetsDeclaration, $tips);
+    }
+
+    protected function getMessage(string $ruleName, string $subject): string
+    {
+        return $this->prepareMessage($ruleName, sprintf('%s should have only one public method', $subject));
+    }
+}

src/Rule/Extractor/Declaration/OnePublicMethodExtractor.php

@@ -0,0 +1,29 @@
+<?php declare(strict_types=1);
+
+namespace PHPat\Rule\Extractor\Declaration;
+
+use PhpParser\Node;
+use PHPStan\Analyser\Scope;
+use PHPStan\Node\InClassNode;
+use PHPStan\Reflection\MethodReflection;
+use ReflectionClass;
+use ReflectionMethod;
+
+trait OnePublicMethodExtractor
+{
+    public function getNodeType(): string
+    {
+        return InClassNode::class;
+    }
+
+    /**
+     * @param InClassNode $node
+     */
+    protected function meetsDeclaration(Node $node, Scope $scope): bool
+    {
+        $reflectionClass = new ReflectionClass($node->getClassReflection()->getName());
+        $methods = $reflectionClass->getMethods(ReflectionMethod::IS_PUBLIC);
+
+        return count($methods) === 1;
+    }
+}

src/Test/Builder/AssertionStep.php

@@ -5,6 +5,7 @@
 use PHPat\Rule\Assertion\Declaration\ShouldBeAbstract\ShouldBeAbstract;
 use PHPat\Rule\Assertion\Declaration\ShouldBeFinal\ShouldBeFinal;
 use PHPat\Rule\Assertion\Declaration\ShouldBeReadonly\ShouldBeReadonly;
+use PHPat\Rule\Assertion\Declaration\ShouldHaveOnlyOnePublicMethod\ShouldHaveOnlyOnePublicMethod;
 use PHPat\Rule\Assertion\Declaration\ShouldNotBeAbstract\ShouldNotBeAbstract;
 use PHPat\Rule\Assertion\Declaration\ShouldNotBeFinal\ShouldNotBeFinal;
 use PHPat\Rule\Assertion\Relation\CanOnlyDepend\CanOnlyDepend;
@@ -100,4 +101,11 @@ public function shouldExtend(): TargetStep
 
         return new TargetStep($this->rule);
     }
+
+    public function shouldHaveOnlyOnePublicMethod(): Rule
+    {
+        $this->rule->assertion = ShouldHaveOnlyOnePublicMethod::class;
+
+        return new BuildStep($this->rule);
+    }
 }

tests/fixtures/Special/ClassWithOnePublicMethod.php

@@ -0,0 +1,13 @@
+<?php declare(strict_types=1);
+
+namespace Tests\PHPat\fixtures\Special;
+
+class ClassWithOnePublicMethod
+{
+    public const CONSTANT = 'constant';
+    public string $property = 'property';
+
+    public function publicMethod(): bool {
+        return true;
+    }
+}

tests/unit/rules/ShouldHaveOnlyOnePublicMethod/ClassWithOnlyOnePublicMethodTest.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace Tests\PHPat\unit\rules\ShouldHaveOnlyOnePublicMethod;
+
+use PHPat\Configuration;
+use PHPat\Rule\Assertion\Declaration\ShouldHaveOnlyOnePublicMethod\HasOnlyOnePublicMethodRule;
+use PHPat\Rule\Assertion\Declaration\ShouldHaveOnlyOnePublicMethod\ShouldHaveOnlyOnePublicMethod;
+use PHPat\Selector\Classname;
+use PHPat\Statement\Builder\StatementBuilderFactory;
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+use PHPStan\Type\FileTypeMapper;
+use Tests\PHPat\fixtures\FixtureClass;
+use Tests\PHPat\unit\FakeTestParser;
+
+/**
+ * @extends RuleTestCase<HasOnlyOnePublicMethodRule>
+ * @internal
+ * @coversNothing
+ */
+class ClassWithOnlyOnePublicMethodTest extends RuleTestCase
+{
+    public const RULE_NAME = 'test_FixtureClassShouldHaveOnlyOnePublicMethod';
+
+    public function testRule(): void
+    {
+        $this->analyse(['tests/fixtures/FixtureClass.php'], [
+            [sprintf('%s should have only one public method', FixtureClass::class), 29],
+        ]);
+    }
+
+    protected function getRule(): Rule
+    {
+        $testParser = FakeTestParser::create(
+            self::RULE_NAME,
+            ShouldHaveOnlyOnePublicMethod::class,
+            [new Classname(FixtureClass::class, false)],
+            []
+        );
+
+        return new HasOnlyOnePublicMethodRule(
+            new StatementBuilderFactory($testParser),
+            new Configuration(false, true, false),
+            $this->createReflectionProvider(),
+            self::getContainer()->getByType(FileTypeMapper::class)
+        );
+    }
+
+}

tests/unit/rules/ShouldHaveOnlyOnePublicMethod/GoodImplementationClassWithOnlyOnePublicMethodTest.php

@@ -0,0 +1,48 @@
+<?php
+
+namespace Tests\PHPat\unit\rules\ShouldHaveOnlyOnePublicMethod;
+
+use PHPat\Configuration;
+use PHPat\Rule\Assertion\Declaration\ShouldHaveOnlyOnePublicMethod\HasOnlyOnePublicMethodRule;
+use PHPat\Rule\Assertion\Declaration\ShouldHaveOnlyOnePublicMethod\ShouldHaveOnlyOnePublicMethod;
+use PHPat\Selector\Classname;
+use PHPat\Statement\Builder\StatementBuilderFactory;
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+use PHPStan\Type\FileTypeMapper;
+use Tests\PHPat\fixtures\FixtureClass;
+use Tests\PHPat\fixtures\Special\ClassWithOnePublicMethod;
+use Tests\PHPat\unit\FakeTestParser;
+
+/**
+ * @extends RuleTestCase<HasOnlyOnePublicMethodRule>
+ * @internal
+ * @coversNothing
+ */
+class GoodImplementationClassWithOnlyOnePublicMethodTest extends RuleTestCase
+{
+    public const RULE_NAME = 'test_FixtureClassShouldHaveOnlyOnePublicMethod';
+
+    public function testRule(): void
+    {
+        $this->analyse(['tests/fixtures/Special/ClassWithOnePublicMethod.php'], []);
+    }
+
+    protected function getRule(): Rule
+    {
+        $testParser = FakeTestParser::create(
+            self::RULE_NAME,
+            ShouldHaveOnlyOnePublicMethod::class,
+            [new Classname(ClassWithOnePublicMethod::class, false)],
+            []
+        );
+
+        return new HasOnlyOnePublicMethodRule(
+            new StatementBuilderFactory($testParser),
+            new Configuration(false, true, false),
+            $this->createReflectionProvider(),
+            self::getContainer()->getByType(FileTypeMapper::class)
+        );
+    }
+
+}