NullPointerException: because this method call was *not* stubbed correctly - scala

Question

I am trying to run this test case in scala using mockito but i see the following error. can anyone suggest to me what am I doing wrong?
This is the Test case that I am running
Test case
class MailerServiceSpec extends BaseSpec {
val http: HttpExt = mock[HttpExt]
val mailService: NotificationService = mock[NotificationService]
val rawJobResponse: JsObject = Json.obj(("aman","verma"))
"Send Emails to multiple/single user" should {
"send email to user" in {
when(http.singleRequest(any[HttpRequest], any[HttpsConnectionContext], any[ConnectionPoolSettings], any[LoggingAdapter])) thenReturn
future(HttpResponse(status = StatusCodes.OK, entity = httpEntity(rawJobResponse)))
whenReady(mailService.sendMessage(any[String],any[String],any[String])(any[ExecutionContext])){ result =>
assert(result == Done)
}
}
}
}
This is the sendMessage method of mailerService that I want to test.
NotificationService.scala
override def sendMessage(receivers: List[String], subject: String, content: String)(implicit
ec: ExecutionContext
): Future[Done] = {
val notification = Notification(
recipients = receivers,
cc = Nil,
bcc = Nil,
sender = sender,
htmlBody = content,
htmlTitle = subject
)
val httpHeader = RawHeader("SENDGRID_API_KEY", sendgridApiKey)
(for {
entity <- Marshal(notification).to[MessageEntity]
_ <- makeHttpRequest(
HttpRequest(POST, notificationEmailUrl, entity = entity).addHeader(httpHeader)
)
} yield Done).andThen {
case Failure(exception) => logger.error("Failed to send email", exception)
}
}
Error
You have a NullPointerException here:
-> at org.scalatest.concurrent.ScalaFutures$$anon$1.futureValueImpl(ScalaFutures.scala:294)
because this method call was *not* stubbed correctly:
-> at scala.Option.orElse(Option.scala:477)
notificationService.sendMessage(
null,
null,
null,
null
);

Answer 1

You are calling notificationService in your test but it's a mock and you didn't define its behaviour.
I think you don't want to mock it but build a real NotificationService, otherwise you're just testing nothing.