FSM testing

SyncTestingFSMExampleSpec.scala

import akka.actor.testkit.typed.scaladsl.BehaviorTestKit
import akka.actor.typed.Behavior
import akka.actor.typed.scaladsl.AbstractBehavior
import org.scalatest.Matchers
import org.scalatest.WordSpec

object SyncTestingFSMExampleSpec {

  sealed trait Command
  final case class Type(c: Char) extends Command
  final case class CapsLock(on: Boolean) extends Command
  final case object Enter extends Command

  final case class NormalMode(text: String) extends AbstractBehavior[Command] {
    override def onMessage(msg: Command): Behavior[Command] = {
      msg match {
        case Type(c) ⇒
          NormalMode(text + c)
        case CapsLock(on) ⇒
          if (on) CapsMode(text)
          else this
        case Enter ⇒
          println(text)
          NormalMode("")
      }
    }
  }

  final case class CapsMode(text: String) extends AbstractBehavior[Command] {
    override def onMessage(msg: Command): Behavior[Command] = {
      msg match {
        case Type(c) ⇒
          CapsMode(text + c.toUpper)
        case CapsLock(on) ⇒
          if (on) this
          else NormalMode(text)
        case Enter ⇒
          println(text)
          CapsMode("")
      }
    }
  }

}

class SyncTestingFSMExampleSpec extends WordSpec with Matchers {

  import SyncTestingFSMExampleSpec._

  "FSM testing" must {

    "support support inspecting state" in {
      val testKit = BehaviorTestKit(NormalMode(""))

      testKit.run(Type('a'))
      testKit.currentBehavior should ===(NormalMode("a"))

      testKit.run(CapsLock(on = true))
      testKit.currentBehavior should ===(CapsMode("a"))

      testKit.run(Type('b'))
      testKit.currentBehavior should ===(CapsMode("aB"))
    }
  }

}

SyncTestingFSMMockitoExampleSpec

import akka.actor.testkit.typed.scaladsl.BehaviorTestKit
import akka.actor.typed.Behavior
import akka.actor.typed.scaladsl.Behaviors
import org.mockito.Mockito._
import org.scalatest.Matchers
import org.scalatest.WordSpec
import org.scalatest.mockito.MockitoSugar

object SyncTestingFSMMockitoExampleSpec {

  sealed trait Command
  final case class Type(c: Char) extends Command
  final case class CapsLock(on: Boolean) extends Command
  final case object Enter extends Command

  class TestFSM {

    def normalMode(text: String): Behavior[Command] =
      Behaviors.receiveMessage {
        case Type(c) ⇒
          normalMode(text + c)
        case CapsLock(on) ⇒
          if (on) capsMode(text)
          else Behaviors.same
        case Enter ⇒
          println(text)
          normalMode("")
      }

    def capsMode(text: String): Behavior[Command] =
      Behaviors.receiveMessage {
        case Type(c) ⇒
          capsMode(text + c.toUpper)
        case CapsLock(on) ⇒
          if (on) Behaviors.same
          else normalMode(text)
        case Enter ⇒
          println(text)
          capsMode("")
      }

  }

}

class SyncTestingFSMMockitoExampleSpec extends WordSpec with Matchers with MockitoSugar {

  import SyncTestingFSMMockitoExampleSpec._

  "FSM testing" must {

    "support support inspecting state" in {

      val testFSM = spy(new TestFSM)

      val testKit = BehaviorTestKit(testFSM.normalMode(""))
      verify(testFSM).normalMode("")

      testKit.run(Type('a'))
      verify(testFSM).normalMode("a")

      testKit.run(CapsLock(on = true))
      verify(testFSM).capsMode("a")

      testKit.run(Type('b'))
      verify(testFSM).capsMode("aB")
    }
  }

}