Report error when trying to configure a non existing method on MockObject

Author: VincentLanglet

src/Rules/PHPUnit/MockMethodCallRule.php

@@ -0,0 +1,55 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\PHPUnit;
+
+use PhpParser\Node;
+use PHPStan\Analyser\Scope;
+use PHPStan\Type\IntersectionType;
+use PHPStan\Type\ObjectType;
+use PHPUnit\Framework\MockObject\MockObject;
+
+/**
+ * @implements \PHPStan\Rules\Rule<\PhpParser\Node\Expr\MethodCall>
+ */
+class MockMethodCallRule implements \PHPStan\Rules\Rule
+{
+
+	public function getNodeType(): string
+	{
+		return Node\Expr\MethodCall::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		/** @var Node\Expr\MethodCall $node */
+		$node = $node;
+
+		if (!$node->name instanceof Node\Identifier || $node->name->name !== 'method') {
+			return [];
+		}
+
+		if (count($node->args) < 1) {
+			return [];
+		}
+
+		$method = $node->args[0]->value->value;
+		$type = $scope->getType($node->var);
+
+		if (
+			$type instanceof IntersectionType
+			&& $type->isSubTypeOf(new ObjectType(MockObject::class))
+			&& !$type->hasMethod($method)->yes()
+		) {
+			return [
+				sprintf(
+					'Trying to mock an undefined method %s() on class %s.',
+					$method,
+					\implode('&', $type->getReferencedClasses())
+				),
+			];
+		}
+
+		return [];
+	}
+
+}

tests/Rules/PHPUnit/MockMethodCallRuleTest.php

@@ -0,0 +1,42 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\PHPUnit;
+
+use PHPStan\Rules\Rule;
+
+/**
+ * @extends \PHPStan\Testing\RuleTestCase<MockMethodCallRule>
+ */
+class MockMethodCallRuleTest extends \PHPStan\Testing\RuleTestCase
+{
+
+	protected function getRule(): Rule
+	{
+		return new MockMethodCallRule();
+	}
+
+	public function testRule(): void
+	{
+		$this->analyse([__DIR__ . '/data/mock-method-call.php'], [
+			[
+				'Trying to mock an undefined method doBadThing() on class MockMethodCall\Bar&PHPUnit\Framework\MockObject\MockObject.',
+				15,
+			],
+			[
+				'Trying to mock an undefined method doBadThing() on class MockMethodCall\Bar&PHPUnit\Framework\MockObject\MockObject.',
+				20,
+			],
+		]);
+	}
+
+	/**
+	 * @return string[]
+	 */
+	public static function getAdditionalConfigFiles(): array
+	{
+		return [
+			__DIR__ . '/../../../extension.neon',
+		];
+	}
+
+}

tests/Rules/PHPUnit/data/mock-method-call.php

@@ -0,0 +1,43 @@
+<?php declare(strict_types = 1);
+
+namespace MockMethodCall;
+
+class Foo extends \PHPUnit\Framework\TestCase
+{
+
+	public function testGoodMethod()
+	{
+		$this->createMock(Bar::class)->method('doThing');
+	}
+
+	public function testBadMethod()
+	{
+		$this->createMock(Bar::class)->method('doBadThing');
+	}
+
+	public function testBadMethodWithExpectation()
+	{
+		$this->createMock(Bar::class)->expects($this->once())->method('doBadThing');
+	}
+
+	public function testWithAnotherObject()
+	{
+		$bar = new BarWithMethod();
+		$bar->method('doBadThing');
+	}
+
+}
+
+class Bar {
+	public function doThing()
+	{
+		return 1;
+	}
+};
+
+class BarWithMethod {
+	public function method(string $string)
+	{
+		return $string;
+	}
+};