public void CatsByOwnerGenderTest() { List <RequestModel> ownerList = new List <RequestModel> { new RequestModel { Name = "Bob", Age = 23, Gender = "Male", Pets = new List <Pet> { new Pet { Name = "Garfield", Type = "Cat" } } } }; List <ResponseModel> listOfPets = new List <ResponseModel> { new ResponseModel { Gender = "Male", Names = new List <string> { "Garfield" } } }; var helper = new Mock <IPetsRepository>(); var petsController = new PetsController(helper.Object); helper.Setup(p => p.GetOwners <List <RequestModel> >()).Returns(ownerList); helper.Setup(p => p.GetCatsByOwnerGender <List <ResponseModel> >(ownerList)).Returns(listOfPets); var pets = petsController.GetCatsByOwnerGender(); Assert.True(listOfPets[0].Gender == pets[0].Gender); Assert.True(listOfPets[0].Names.Count == pets[0].Names.Count); }