public void EditCustomer(bool customerExists) { var c = new Customer(); _repoMock.Setup(repo => repo.AddEditCustomer(c)).Returns(customerExists ? c : null); _repoMock.Setup(repo => repo.GetCustomer_Id(0)).Returns(customerExists ? c : null); var service = new CustomerService(_repoMock.Object); var res = service.AddEditCustomer(c, true); if (customerExists) { Assert.NotNull(res.Customer); } else { Assert.Null(res.Customer); } Assert.Equal(customerExists, res.Exists); }