PHPStan PHPUnit extensions and rules

• PHPStan
• PHPUnit

This extension provides following features:

• createMock(), getMockForAbstractClass() and getMockFromWsdl() methods return an intersection type (see the detailed explanation of intersection types) of the mock object and the mocked class so that both methods from the mock object (like expects) and from the mocked class are available on the object.
• getMock() called on MockBuilder is also supported.
• Interprets Foo|PHPUnit_Framework_MockObject_MockObject in phpDoc so that it results in an intersection type instead of a union type.
• Defines early terminating method calls for the PHPUnit\Framework\TestCase class to prevent undefined variable errors.
• Specifies types of expressions passed to various assert methods like assertInstanceOf, assertTrue, assertInternalType etc.
• Combined with PHPStan's level 4, it points out always-true and always-false asserts like assertTrue(true) etc.

It also contains this strict framework-specific rules (can be enabled separately):

• Check that you are not using assertSame() with true as expected value. assertTrue() should be used instead.
• Check that you are not using assertSame() with false as expected value. assertFalse() should be used instead.
• Check that you are not using assertSame() with null as expected value. assertNull() should be used instead.
• Check that you are not using assertSame() with count($variable) as second parameter. assertCount($variable) should be used instead.

How to document mock objects in phpDocs?

If you need to configure the mock even after you assign it to a property or return it from a method, you should add PHPUnit_Framework_MockObject_MockObject to the phpDoc:

/**
 * @return Foo&PHPUnit_Framework_MockObject_MockObject
 */
private function createFooMock()
{
    return $this->createMock(Foo::class);
}

public function testSomething()
{
    $fooMock = $this->createFooMock();
    $fooMock->method('doFoo')->will($this->returnValue('test'));
    $fooMock->doFoo();
}

Please note that the correct syntax for intersection types is Foo&PHPUnit_Framework_MockObject_MockObject. Foo|PHPUnit_Framework_MockObject_MockObject is also supported, but only for ecosystem and legacy reasons.

If the mock is fully configured and only the methods of the mocked class are supposed to be called on the value, it's fine to typehint only the mocked class:

/** @var Foo */
private $foo;

protected function setUp()
{
    $fooMock = $this->createMock(Foo::class);
    $fooMock->method('doFoo')->will($this->returnValue('test'));
    $this->foo = $fooMock;
}

public function testSomething()
{
    $this->foo->doFoo();
    // $this->foo->method() and expects() can no longer be called
}

Installation

To use this extension, require it in Composer:

composer require --dev phpstan/phpstan-phpunit

If you also install phpstan/extension-installer then you're all set!