fishForSpecificMessage #20118

akka-testkit/src/main/scala/akka/testkit/TestKit.scala

@@ -439,6 +439,21 @@ trait TestKitBase {
     recv
   }
 
+  /**
+   * Same as `fishForMessage`, but gets a different partial function and returns properly typed message.
+   */
+  def fishForSpecificMessage[T](max: Duration = Duration.Undefined, hint: String = "")(f: PartialFunction[Any, T]): T = {
+    val _max = remainingOrDilated(max)
+    val end = now + _max
+    @tailrec
+    def recv: T = {
+      val o = receiveOne(end - now)
+      assert(o ne null, s"timeout (${_max}) during fishForSpecificMessage, hint: $hint")
+      if (f.isDefinedAt(o)) f(o) else recv
+    }
+    recv
+  }
+
   /**
    * Same as `expectMsgType[T](remainingOrDefault)`, but correctly treating the timeFactor.
    */

akka-testkit/src/test/scala/akka/testkit/TestProbeSpec.scala

@@ -141,6 +141,37 @@ class TestProbeSpec extends AkkaSpec with DefaultTimeout {
       expectMsgAllClassOf(5 seconds, classOf[Int]) should ===(Seq(42))
     }
 
+    "be able to fish for messages" in {
+      val probe = TestProbe()
+      probe.ref ! "hallo"
+      probe.ref ! "welt"
+      probe.ref ! "fishForMe"
+      probe.ref ! "done"
+
+      probe.fishForMessage() {
+        case "fishForMe" ⇒ true
+        case _           ⇒ false
+      }
+
+      probe.expectMsg(1 second, "done")
+    }
+
+    "be able to fish for specific messages" in {
+      val probe = TestProbe()
+      probe.ref ! "hallo"
+      probe.ref ! "welt"
+      probe.ref ! "fishForMe"
+      probe.ref ! "done"
+
+      val msg: String = probe.fishForSpecificMessage() {
+        case msg @ "fishForMe" ⇒ msg
+      }
+
+      msg should be("fishForMe")
+
+      probe.expectMsg(1 second, "done")
+    }
+
     "be able to ignore primitive types" in {
       ignoreMsg { case 42 ⇒ true }
       testActor ! 42

project/MiMa.scala

@@ -1043,7 +1043,12 @@ object MiMa extends AutoPlugin {
         // #22277 changes to internal classes
         ProblemFilters.exclude[DirectMissingMethodProblem]("akka.remote.transport.netty.TcpServerHandler.this"),
         ProblemFilters.exclude[DirectMissingMethodProblem]("akka.remote.transport.netty.TcpClientHandler.this"),
-        ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.remote.transport.netty.TcpHandlers.log")
+        ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.remote.transport.netty.TcpHandlers.log"),
+
+        // #22374 introduce fishForSpecificMessage in TestKit
+        ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.testkit.TestKitBase.fishForSpecificMessage$default$1"),
+        ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.testkit.TestKitBase.fishForSpecificMessage"),
+        ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.testkit.TestKitBase.fishForSpecificMessage$default$2")
       )
       // make sure that
       //  * this list ends with the latest released version number