Fix 27338 - Allow passing an actor system to the typed.ActorTestKit (#28871)

* Add apply methods for typed ActorTestKit allowing for passing an ActorSystem

akka-actor-testkit-typed/src/main/mima-filters/2.6.4.backwards.excludes/27338-ActorTestKit-system.excludes

@@ -0,0 +1,3 @@
+# #27338 allow passing ActorSystem to ActorTestKit
+ProblemFilters.exclude[IncompatibleSignatureProblem]("akka.actor.testkit.typed.scaladsl.ActorTestKit.internalSystem")
+ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.actor.testkit.typed.scaladsl.ActorTestKit.this")

akka-actor-testkit-typed/src/main/scala/akka/actor/testkit/typed/javadsl/ActorTestKit.scala

@@ -21,10 +21,8 @@ import akka.util.JavaDurationConverters._
 object ActorTestKit {
 
   /**
-   * Create a testkit named from the class that is calling this method.
+   * Create a testkit named from the ActorTestKit class.
    *
-   * It will create an [[akka.actor.typed.ActorSystem]] with this name,
-   * e.g. threads will include the name.
    * When the test has completed you should terminate the `ActorSystem` and
    * the testkit with [[ActorTestKit#shutdownTestKit]].
    *
@@ -36,7 +34,19 @@ object ActorTestKit {
     new ActorTestKit(scaladsl.ActorTestKit(TestKitUtils.testNameFromCallStack(classOf[ActorTestKit])))
 
   /**
-   * Create a named testkit.
+   * Create a testkit from the provided actor system.
+   *
+   * When the test has completed you should terminate the `ActorSystem` and
+   * the testkit with [[ActorTestKit#shutdownTestKit]].
+   *
+   * Config loaded from the provided actor if that exists, otherwise
+   * using default configuration from the reference.conf resources that ship with the Akka libraries.
+   */
+  def create(system: ActorSystem[_]): ActorTestKit =
+    new ActorTestKit(scaladsl.ActorTestKit(system))
+
+  /**
+   * Create a testkit using the provided name.
    *
    * It will create an [[akka.actor.typed.ActorSystem]] with this name,
    * e.g. threads will include the name.
@@ -51,11 +61,11 @@ object ActorTestKit {
     new ActorTestKit(scaladsl.ActorTestKit(name))
 
   /**
-   * Create a testkit named from the class that is calling this method,
+   * Create a testkit named from the ActorTestKit class,
    * and use a custom config for the actor system.
    *
-   * It will create an [[akka.actor.typed.ActorSystem]] with this name,
-   * e.g. threads will include the name.
+   * It will also used the provided customConfig provided to create the `ActorSystem`
+   *
    * When the test has completed you should terminate the `ActorSystem` and
    * the testkit with [[ActorTestKit#shutdownTestKit]].
    */
@@ -63,10 +73,14 @@ object ActorTestKit {
     new ActorTestKit(scaladsl.ActorTestKit(TestKitUtils.testNameFromCallStack(classOf[ActorTestKit]), customConfig))
 
   /**
-   * Create a named testkit, and use a custom config for the actor system.
+   * Create a test kit named based on the provided name,
+   * and uses the provided custom config for the actor system.
    *
    * It will create an [[akka.actor.typed.ActorSystem]] with this name,
    * e.g. threads will include the name.
+   *
+   * It will also used the provided customConfig provided to create the `ActorSystem`
+   *
    * When the test has completed you should terminate the `ActorSystem` and
    * the testkit with [[ActorTestKit#shutdownTestKit]].
    */
@@ -74,11 +88,14 @@ object ActorTestKit {
     new ActorTestKit(scaladsl.ActorTestKit(name, customConfig))
 
   /**
-   * Create a named testkit, and use a custom config for the actor system,
-   * and a custom [[akka.actor.testkit.typed.TestKitSettings]]
+   * Create an [[akka.actor.typed.ActorSystem]] named based on the provided name,
+   * use the provided custom config for the actor system, and the testkit will use the provided setting.
    *
    * It will create an [[akka.actor.typed.ActorSystem]] with this name,
    * e.g. threads will include the name.
+   *
+   * It will also used the provided customConfig provided to create the `ActorSystem`, and provided setting.
+   *
    * When the test has completed you should terminate the `ActorSystem` and
    * the testkit with [[ActorTestKit#shutdownTestKit]].
    */

akka-actor-testkit-typed/src/main/scala/akka/actor/testkit/typed/javadsl/TestKitJunitResource.scala

@@ -54,6 +54,11 @@ final class TestKitJunitResource(_kit: ActorTestKit) extends ExternalResource {
    */
   def this() = this(ActorTestKit.create(TestKitUtils.testNameFromCallStack(classOf[TestKitJunitResource])))
 
+  /**
+   * Use a custom [[akka.actor.typed.ActorSystem]] for the actor system.
+   */
+  def this(system: ActorSystem[_]) = this(ActorTestKit.create(system))
+
   /**
    * Use a custom config for the actor system.
    */

akka-actor-testkit-typed/src/main/scala/akka/actor/testkit/typed/scaladsl/ActorTestKit.scala

@@ -26,7 +26,39 @@ import org.slf4j.LoggerFactory
 object ActorTestKit {
 
   /**
-   * Create a testkit named from the class that is calling this method.
+   * Create a testkit named from the ActorTestKit class.
+   *
+   * When the test has completed you should terminate the `ActorSystem` and
+   * the testkit with [[ActorTestKit#shutdownTestKit]].
+   *
+   * Config loaded from `application-test.conf` if that exists, otherwise
+   * using default configuration from the reference.conf resources that ship with the Akka libraries.
+   * The application.conf of your project is not used in this case.
+   */
+  def apply(): ActorTestKit = {
+    val system = ActorSystem(
+      ActorTestKitGuardian.testKitGuardian,
+      TestKitUtils.testNameFromCallStack(classOf[ActorTestKit]),
+      ApplicationTestConfig)
+    new ActorTestKit(system, system, settings = None)
+  }
+
+  /**
+   * Create a testkit from the provided actor system.
+   *
+   * When the test has completed you should terminate the `ActorSystem` and
+   * the testkit with [[ActorTestKit#shutdownTestKit]].
+   *
+   * Config loaded from the provided actor if that exists, otherwise
+   * using default configuration from the reference.conf resources that ship with the Akka libraries.
+   */
+  def apply(system: ActorSystem[_]): ActorTestKit = {
+    val testKitGuardian = system.systemActorOf(ActorTestKitGuardian.testKitGuardian, "test")
+    new ActorTestKit(system, testKitGuardian, settings = None)
+  }
+
+  /**
+   * Create a testkit using the provided name.
    *
    * It will create an [[akka.actor.typed.ActorSystem]] with this name,
    * e.g. threads will include the name.
@@ -37,64 +69,64 @@ object ActorTestKit {
    * using default configuration from the reference.conf resources that ship with the Akka libraries.
    * The application.conf of your project is not used in this case.
    */
-  def apply(): ActorTestKit =
-    new ActorTestKit(
-      name = TestKitUtils.testNameFromCallStack(classOf[ActorTestKit]),
-      config = ApplicationTestConfig,
-      settings = None)
+  def apply(name: String): ActorTestKit = {
+    val system =
+      ActorSystem(ActorTestKitGuardian.testKitGuardian, TestKitUtils.scrubActorSystemName(name), ApplicationTestConfig)
+    new ActorTestKit(system, system, settings = None)
+  }
 
   /**
-   * Create a named testkit.
-   *
-   * It will create an [[akka.actor.typed.ActorSystem]] with this name,
-   * e.g. threads will include the name.
-   * When the test has completed you should terminate the `ActorSystem` and
-   * the testkit with [[ActorTestKit#shutdownTestKit]].
-   *
-   * Config loaded from `application-test.conf` if that exists, otherwise
-   * using default configuration from the reference.conf resources that ship with the Akka libraries.
-   * The application.conf of your project is not used in this case.
-   */
-  def apply(name: String): ActorTestKit =
-    new ActorTestKit(name = TestKitUtils.scrubActorSystemName(name), config = ApplicationTestConfig, settings = None)
-
-  /**
-   * Create a testkit named from the class that is calling this method,
+   * Create a testkit named from the ActorTestKit class,
    * and use a custom config for the actor system.
    *
-   * It will create an [[akka.actor.typed.ActorSystem]] with this name,
-   * e.g. threads will include the name.
+   * It will also used the provided customConfig provided to create the `ActorSystem`
+   *
    * When the test has completed you should terminate the `ActorSystem` and
    * the testkit with [[ActorTestKit#shutdownTestKit]].
    */
-  def apply(customConfig: Config): ActorTestKit =
-    new ActorTestKit(
-      name = TestKitUtils.testNameFromCallStack(classOf[ActorTestKit]),
-      config = customConfig,
-      settings = None)
+  def apply(customConfig: Config): ActorTestKit = {
+    val system = ActorSystem(
+      ActorTestKitGuardian.testKitGuardian,
+      TestKitUtils.testNameFromCallStack(classOf[ActorTestKit]),
+      customConfig)
+    new ActorTestKit(system, system, settings = None)
+  }
 
   /**
-   * Create a named testkit, and use a custom config for the actor system.
+   * Create a test kit named based on the provided name,
+   * and uses the provided custom config for the actor system.
    *
    * It will create an [[akka.actor.typed.ActorSystem]] with this name,
    * e.g. threads will include the name.
+   *
+   * It will also used the provided customConfig provided to create the `ActorSystem`
+   *
    * When the test has completed you should terminate the `ActorSystem` and
    * the testkit with [[ActorTestKit#shutdownTestKit]].
    */
-  def apply(name: String, customConfig: Config): ActorTestKit =
-    new ActorTestKit(name = TestKitUtils.scrubActorSystemName(name), config = customConfig, settings = None)
+  def apply(name: String, customConfig: Config): ActorTestKit = {
+    val system =
+      ActorSystem(ActorTestKitGuardian.testKitGuardian, TestKitUtils.scrubActorSystemName(name), customConfig)
+    new ActorTestKit(system, system, settings = None)
+  }
 
   /**
-   * Create a named testkit, and use a custom config for the actor system,
-   * and a custom [[akka.actor.testkit.typed.TestKitSettings]]
+   * Create an [[akka.actor.typed.ActorSystem]] named based on the provided name,
+   * use the provided custom config for the actor system, and the testkit will use the provided setting.
    *
    * It will create an [[akka.actor.typed.ActorSystem]] with this name,
    * e.g. threads will include the name.
+   *
+   * It will also used the provided customConfig provided to create the `ActorSystem`, and provided setting.
+   *
    * When the test has completed you should terminate the `ActorSystem` and
    * the testkit with [[ActorTestKit#shutdownTestKit]].
    */
-  def apply(name: String, customConfig: Config, settings: TestKitSettings): ActorTestKit =
-    new ActorTestKit(name = TestKitUtils.scrubActorSystemName(name), config = customConfig, settings = Some(settings))
+  def apply(name: String, customConfig: Config, settings: TestKitSettings): ActorTestKit = {
+    val system =
+      ActorSystem(ActorTestKitGuardian.testKitGuardian, TestKitUtils.scrubActorSystemName(name), customConfig)
+    new ActorTestKit(system, system, settings = Some(settings))
+  }
 
   /**
    * Shutdown the given [[akka.actor.typed.ActorSystem]] and block until it shuts down,
@@ -131,10 +163,17 @@ object ActorTestKit {
  *
  * For synchronous testing of a `Behavior` see [[BehaviorTestKit]]
  */
-final class ActorTestKit private[akka] (val name: String, val config: Config, settings: Option[TestKitSettings]) {
+final class ActorTestKit private[akka] (
+    val internalSystem: ActorSystem[_],
+    internalTestKitGuardian: ActorRef[ActorTestKitGuardian.TestKitCommand],
+    settings: Option[TestKitSettings]) {
+
+  val name = internalSystem.name
+
+  val config = internalSystem.settings.config
 
   // avoid slf4j noise by touching it first from single thread #28673
-  LoggerFactory.getLogger(name).debug("Starting ActorTestKit")
+  LoggerFactory.getLogger(internalSystem.name).debug("Starting ActorTestKit")
 
   implicit def testKitSettings: TestKitSettings =
     settings.getOrElse(TestKitSettings(system))
@@ -142,9 +181,6 @@ final class ActorTestKit private[akka] (val name: String, val config: Config, se
   /**
    * INTERNAL API
    */
-  @InternalApi private[akka] val internalSystem: ActorSystem[ActorTestKitGuardian.TestKitCommand] =
-    ActorSystem(ActorTestKitGuardian.testKitGuardian, name, config)
-
   implicit def system: ActorSystem[Nothing] = internalSystem
 
   private val childName: Iterator[String] = Iterator.from(0).map(_.toString)
@@ -172,7 +208,9 @@ final class ActorTestKit private[akka] (val name: String, val config: Config, se
    * guardian
    */
   def spawn[T](behavior: Behavior[T], props: Props): ActorRef[T] =
-    Await.result(internalSystem.ask(ActorTestKitGuardian.SpawnActorAnonymous(behavior, _, props)), timeout.duration)
+    Await.result(
+      internalTestKitGuardian.ask(ActorTestKitGuardian.SpawnActorAnonymous(behavior, _, props)),
+      timeout.duration)
 
   /**
    * Spawn the given behavior. This is created as a child of the test kit
@@ -186,7 +224,9 @@ final class ActorTestKit private[akka] (val name: String, val config: Config, se
    * guardian
    */
   def spawn[T](behavior: Behavior[T], name: String, props: Props): ActorRef[T] =
-    Await.result(internalSystem.ask(ActorTestKitGuardian.SpawnActor(name, behavior, _, props)), timeout.duration)
+    Await.result(
+      internalTestKitGuardian.ask(ActorTestKitGuardian.SpawnActor(name, behavior, _, props)),
+      timeout.duration)
 
   /**
    * Stop the actor under test and wait until it terminates.
@@ -195,7 +235,7 @@ final class ActorTestKit private[akka] (val name: String, val config: Config, se
    */
   def stop[T](ref: ActorRef[T], max: FiniteDuration = timeout.duration): Unit =
     try {
-      Await.result(internalSystem.ask { x: ActorRef[ActorTestKitGuardian.Ack.type] =>
+      Await.result(internalTestKitGuardian.ask { x: ActorRef[ActorTestKitGuardian.Ack.type] =>
         ActorTestKitGuardian.StopActor(ref, x)
       }, max)
     } catch {

akka-actor-testkit-typed/src/main/scala/akka/actor/testkit/typed/scaladsl/ScalaTestWithActorTestKit.scala

@@ -5,6 +5,7 @@
 package akka.actor.testkit.typed.scaladsl
 
 import akka.actor.testkit.typed.TestKitSettings
+import akka.actor.typed.ActorSystem
 import com.typesafe.config.Config
 import com.typesafe.config.ConfigFactory
 import org.scalatest.{ BeforeAndAfterAll, TestSuite }
@@ -41,6 +42,11 @@ abstract class ScalaTestWithActorTestKit(testKit: ActorTestKit)
    */
   def this() = this(ActorTestKit(ActorTestKitBase.testNameFromCallStack()))
 
+  /**
+   * Use a custom [[akka.actor.typed.ActorSystem]] for the actor system.
+   */
+  def this(system: ActorSystem[_]) = this(ActorTestKit(system))
+
   /**
    * Use a custom config for the actor system.
    */

akka-actor-testkit-typed/src/test/scala/akka/actor/testkit/typed/scaladsl/ActorTestKitSpec.scala

@@ -5,8 +5,10 @@
 package akka.actor.testkit.typed.scaladsl
 
 import akka.Done
-import scala.concurrent.Promise
+import akka.actor.testkit.typed.internal.ActorTestKitGuardian
+import akka.actor.typed.ActorSystem
 
+import scala.concurrent.Promise
 import akka.actor.typed.scaladsl.Behaviors
 import com.typesafe.config.ConfigFactory
 import org.scalatest.BeforeAndAfterAll
@@ -21,6 +23,16 @@ class ActorTestKitSpec extends ScalaTestWithActorTestKit with AnyWordSpecLike wi
       system.name should ===("ActorTestKitSpec")
     }
 
+    "generate a test kit from the provided actor system" in {
+      val config = ConfigFactory.parseString("test.specific-config = yes")
+      val system = ActorSystem(ActorTestKitGuardian.testKitGuardian, "TestActor", config)
+      val testkit2 = ActorTestKit(system)
+      try {
+        testkit2.internalSystem should ===(system)
+        testkit2.system should ===(system)
+      } finally testkit2.shutdownTestKit()
+    }
+
     "generate a default name from the test class" in {
       val testkit2 = ActorTestKit()
       try {
@@ -64,23 +76,18 @@ class ActorTestKitSpec extends ScalaTestWithActorTestKit with AnyWordSpecLike wi
     }
 
     "load application-test.conf by default" in {
-      testKit.config.getString("test.from-application-test") should ===("yes")
       testKit.system.settings.config.getString("test.from-application-test") should ===("yes")
       testKit.system.settings.config.hasPath("test.from-application") should ===(false)
     }
 
     "not load application-test.conf if specific Config given" in {
       val testKit2 = ActorTestKit(ConfigFactory.parseString("test.specific-config = yes"))
-      testKit2.config.getString("test.specific-config") should ===("yes")
       testKit2.system.settings.config.getString("test.specific-config") should ===("yes")
-      testKit2.config.hasPath("test.from-application-test") should ===(false)
       testKit2.system.settings.config.hasPath("test.from-application-test") should ===(false)
       testKit2.system.settings.config.hasPath("test.from-application") should ===(false)
 
       // same if via ScalaTestWithActorTestKit
       val scalaTestWithActorTestKit2 = new ScalaTestWithActorTestKit("test.specific-config = yes") {}
-      scalaTestWithActorTestKit2.testKit.config.getString("test.specific-config") should ===("yes")
-      scalaTestWithActorTestKit2.testKit.config.hasPath("test.from-application-test") should ===(false)
       scalaTestWithActorTestKit2.system.settings.config.hasPath("test.from-application-test") should ===(false)
       scalaTestWithActorTestKit2.testKit.system.settings.config.hasPath("test.from-application") should ===(false)
     }