public async void PostCourier_InvalidModelState()
        {
            _couriersController.ModelState.AddModelError("Name", "Name is required");
            var controllerResponse = await _couriersController.PostAsync(new SaveCourierResource { Name = "" });

            var badRequestResult = Expect.IsType <BadRequestObjectResult>(controllerResponse);
            var errorReturned    = Expect.IsType <List <string> >(badRequestResult.Value);

            Expect.DeepEqual(new List <string> {
                "Name is required"
            }, errorReturned);
        }