add BehaviorTestKit.runOne and .ref (#25013)

akka-testkit-typed/src/main/scala/akka/testkit/typed/internal/BehaviorTestKitImpl.scala

@@ -123,6 +123,8 @@ private[akka] final class BehaviorTestKitImpl[T](_path: ActorPath, _initialBehav
     } catch handleException
   }
 
+  override def runOne(): Unit = run(selfInbox.receiveMessage())
+
   override def signal(signal: Signal): Unit = {
     try {
       currentUncanonical = Behavior.interpretSignal(current, ctx, signal)

akka-testkit-typed/src/main/scala/akka/testkit/typed/javadsl/BehaviorTestKit.scala

@@ -62,6 +62,11 @@ abstract class BehaviorTestKit[T] {
    */
   def selfInbox(): TestInbox[T]
 
+  /**
+   * The self reference of the actor living inside this testkit.
+   */
+  def getRef(): ActorRef[T] = selfInbox.getRef()
+
   /**
    * Requests all the effects. The effects are consumed, subsequent calls will only
    * see new effects.
@@ -107,6 +112,11 @@ abstract class BehaviorTestKit[T] {
    */
   def run(msg: T): Unit
 
+  /**
+   * Send the first message in the selfInbox to the behavior and run it, recording [[Effect]]s.
+   */
+  def runOne(): Unit
+
   /**
    * Send the signal to the beheavior and record any [[Effect]]s
    */

akka-testkit-typed/src/main/scala/akka/testkit/typed/scaladsl/BehaviorTestKit.scala

@@ -63,6 +63,11 @@ trait BehaviorTestKit[T] {
    */
   def selfInbox(): TestInbox[T]
 
+  /**
+   * The self reference of the actor living inside this testkit.
+   */
+  def ref: ActorRef[T] = selfInbox.ref
+
   /**
    * Requests all the effects. The effects are consumed, subsequent calls will only
    * see new effects.
@@ -113,6 +118,11 @@ trait BehaviorTestKit[T] {
    */
   def run(msg: T): Unit
 
+  /**
+   * Send the first message in the selfInbox to the behavior and run it, recording [[Effect]]s.
+   */
+  def runOne(): Unit
+
   /**
    * Send the signal to the beheavior and record any [[Effect]]s
    */