public async void DeleteCourier_DeleteAsyncFailed()
        {
            var deleteAsyncResponse = new CourierResponse("Failed to delete courier");

            _mockedCourierService.Setup(x => x.DeleteAsync(1)).ReturnsAsync(deleteAsyncResponse);

            var controllerResponse = await _couriersController.DeleteAsync(1);

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

            Expect.Equal("Failed to delete courier", errorReturned);
        }