public void Customers_Create() { var aCustomer = new Customer { Id = 0 }; // Set test Create method w/o parameters request.Setup(m => m.Post <Response <Customer> >("customers", aCustomer, null)).Returns(new Response <Customer> { Data = new Customer { Id = 1234 } }); // Test Get method var result = customersProxy.Create(aCustomer); // Verify test Assert.IsNotNull(result); Assert.IsTrue(result.IsSuccessful); Assert.AreEqual(1234, result.Data.Id); }