Mocking Interfaces with PHPUnit

Using the MockBuilder

To mock an interface with PHPUnit we have to pass all methods of the given Interface.

 $reflection = new \ReflectionClass(UserRepositoryInterface::class);

$methods = [];
foreach($reflection->getMethods() as $method) {
    $methods[] = $method->name;
}
$stub = $this->getMockBuilder(UserRepositoryInterface::class)
    ->setMethods($methods)
    ->getMock();

$stub->method('findAll')->willReturn([new UserData()]);

The downside is, that your tests will fail if you rename a interface method, because findAll is just an string an cannot be automatically renamed / refactored by PhpStorm in this way.

Using anonymous classes

Using anonymous classes is more refactor-friedly and works without reflection.

$stub = new class() implements UserRepositoryInterface
{
    public function findAll(): array
    {
        return ['my' => 'data'];
    }
    public function getUserById(int $userId): UserData
    {
        // TODO: Implement getUserById() method.
    }
};

odan/mocking-interface-phpunit.md

Mocking Interfaces with PHPUnit

Using the MockBuilder

Using anonymous classes