NotificationServiceTest.kt

class NotificationServiceTest : Spek({
    describe(".notify") {
        context("when message creation fails") {
            // constants
            val messagingServiceId = "message-service-id"
            val errorCode = 9
            val errorMessage = "error message"


            val restClient = mock<TwilioRestClient>()
            val secretRepository = mock<SecretRepository> {
                on { getTwilloMessagingServiceId() } doReturn messagingServiceId
            }

            val notificationService = NotificationService(restClient, secretRepository)
            val notificationRequest = NotificationRequest("+66", "839992233", "text")

            val mockMessageCreator = mock<MessageCreator> {
                on { create(restClient) } doReturn Message.fromJson(
                        """
                            {
                              "error_code": $errorCode,
                              "error_message": "$errorMessage",
                              "status": "failed"
                            }
                        """.trimIndent(), jacksonObjectMapper())
            }

            // Mock function and stub the invoke method
            val creator = mock<MessageCreatorFactory> {
                on { invoke(any(), any(), any()) } doReturn mockMessageCreator
            }

            val result = notificationService.notify(notificationRequest, creator)

            it("returns `NotificationFailed` with error code and error message") {
                assertThat(result).isEqualTo(NotificationFailed(errorCode, errorMessage))
            }

            it("calls `creator` with right phoneNumber, messagingServiceId and text") {
                // check if `creator` in being invoked with expected arguments
                verify(creator).invoke(PhoneNumber("+66839992233"), messagingServiceId, "text")
            }
        }
    }
})