public async Task TestNoSendableInvoices()
        {
            var mockJobberClient = MockJobberClientBuilder.Create()
                                   .ReturnsDraftInvoices(new List <Invoice>())
                                   .Build();

            var fulfillmentRequest = FulfillmentRequestBuilder.Create(Constants.Intents.SendableInvoices)
                                     .Build();

            var fulfiller = new SendableInvoicesIntentFulfiller();
            var response  = await fulfiller.FulfillAsync(fulfillmentRequest, mockJobberClient.Object);

            response.AssertResponseSpeech("Looks like you have no invoices that need to be sent!");
        }
        public async Task TestMultipleSendableInvoices()
        {
            var Invoices = Enumerable.Range(0, 2).Select(x => new Invoice()).ToList();

            var mockJobberClient = MockJobberClientBuilder.Create()
                                   .ReturnsDraftInvoices(Invoices)
                                   .Build();

            var fulfillmentRequest = FulfillmentRequestBuilder.Create(Constants.Intents.SendableInvoices)
                                     .Build();

            var fulfiller = new SendableInvoicesIntentFulfiller();
            var response  = await fulfiller.FulfillAsync(fulfillmentRequest, mockJobberClient.Object);

            response.AssertResponseSpeech("There are 2 invoices ready to be sent.");
        }