public void CallsServiceWhenSetLeftIsCalledCorrectly() { var request = new SetDataRequest { Data = TestData }; _controller.SetLeft(TestId, request); _diffCheckerServiceMock .Verify( dcs => dcs.SetLeft( It.Is <string>(id => id.Equals(TestId)), It.Is <string>(dataRequest => dataRequest.Equals(TestData))) ); }