getMockBuilder(CookieFormKey::class) ->disableOriginalConstructor() ->getMock(); /** @var DataFormKey | \PHPUnit_Framework_MockObject_MockObject $dataFormKey */ $dataFormKey = $this->getMockBuilder(DataFormKey::class) ->disableOriginalConstructor() ->getMock(); /** @var Observer | \PHPUnit_Framework_MockObject_MockObject $observerObject */ $observerObject = $this->createMock(Observer::class); $observer = new FlushFormKey($cookieFormKey, $dataFormKey); $cookieFormKey->expects($this->once()) ->method('delete'); $dataFormKey->expects($this->once()) ->method('set') ->with(null); $observer->execute($observerObject); } }