Testing Future Objects with ScalaTest - More details at http://lucianomolinari.com/2016/08/07/testing-future-objects-scalatest/

HelloWorld.scala

import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.Future

object HelloWorld {

  val theOneWhoCannotBeNamed = "Voldemort"

  def sayHelloTo(name: String): Future[Option[String]] = {
    Future {
      if (theOneWhoCannotBeNamed.equals(name)) None else Some(getHelloMessage(name))
    }
  }

  def getHelloMessage(name: String): String = {
    s"Hello ${name}, welcome to the future world!"
  }

}

HelloWorldAsyncSpec.scala

import org.scalatest.{AsyncFunSuite, Matchers}

class HelloWorldAsyncSpec extends AsyncFunSuite with Matchers {

  test("A valid message should be returned to a valid name") {
    HelloWorld.sayHelloTo("Harry") map { result =>
      result shouldBe Some("Hello Harry, welcome to the future world!")
    }
  }

  test("No message should be returned to the one who cannot be named") {
    HelloWorld.sayHelloTo("Voldemort") map { result =>
      result shouldBe None
    }
  }

}

HelloWorldSpecWithAwait.scala

import org.scalatest.{FunSuite, Matchers}

import scala.concurrent.Await
import scala.concurrent.duration._

class HelloWorldSpecWithAwait extends FunSuite with Matchers {

  test("A valid message should be returned to a valid name") {
    val result = Await.result(HelloWorld.sayHelloTo("Harry"), 500 millis)
    result shouldBe Some("Hello Harry, welcome to the future world!")
  }

  test("No message should be returned to the one who cannot be named") {
    val result = Await.result(HelloWorld.sayHelloTo("Voldemort"), 500 millis)
    result shouldBe None
  }

}

HelloWorldSpecWithScalaFutures.scala

import org.scalatest.concurrent.ScalaFutures
import org.scalatest.{FunSuite, Matchers}

class HelloWorldSpecWithScalaFutures extends FunSuite with Matchers with ScalaFutures {

  test("A valid message should be returned to a valid name") {
    whenReady(HelloWorld.sayHelloTo("Harry")) { result => 
      result shouldBe Some("Hello Harry, welcome to the future world!")
    }
  }

  test("No message should be returned to the one who cannot be named") {
    whenReady(HelloWorld.sayHelloTo("Voldemort")) { result => 
      result shouldBe None
    }
  }

}