Merge pull request #509 from akka/wip-2174-testkit-trait-∂π

offer TestKitBase trait, see #2174

akka-docs/scala/code/docs/testkit/TestkitDocSpec.scala

@@ -14,6 +14,8 @@ import akka.dispatch.Futures
 import akka.testkit.AkkaSpec
 import akka.testkit.DefaultTimeout
 import akka.testkit.ImplicitSender
+import akka.util.NonFatal
+
 object TestkitDocSpec {
   case object Say42
   case object Unknown
@@ -208,7 +210,7 @@ class TestkitDocSpec extends AkkaSpec with DefaultTimeout with ImplicitSender {
     val probe = TestProbe()
     val future = probe.ref ? "hello"
     probe.expectMsg(0 millis, "hello") // TestActor runs on CallingThreadDispatcher
-    probe.sender ! "world"
+    probe.reply("world")
     assert(future.isCompleted && future.value == Some(Right("world")))
     //#test-probe-reply
   }
@@ -252,4 +254,22 @@ class TestkitDocSpec extends AkkaSpec with DefaultTimeout with ImplicitSender {
     //#event-filter
   }
 
+  "demonstrate TestKitBase" in {
+    //#test-kit-base
+    import akka.testkit.TestKitBase
+
+    class MyTest extends TestKitBase {
+      implicit lazy val system = ActorSystem()
+
+      //#put-your-test-code-here
+      val probe = TestProbe()
+      probe.send(testActor, "hello")
+      try expectMsg("hello") catch { case NonFatal(e) ⇒ system.shutdown(); throw e }
+      //#put-your-test-code-here
+
+      system.shutdown()
+    }
+    //#test-kit-base
+  }
+
 }

akka-docs/scala/testing.rst

@@ -671,6 +671,25 @@ This section contains a collection of known gotchas with some other frameworks,
 which is by no means exhaustive and does not imply endorsement or special
 support.
 
+When you need it to be a trait
+------------------------------
+
+If for some reason it is a problem to inherit from :class:`TestKit` due to it
+being a concrete class instead of a trait, there’s :class:`TestKitBase`:
+
+.. includecode:: code/docs/testkit/TestkitDocSpec.scala
+   :include: test-kit-base
+   :exclude: put-your-test-code-here
+
+The ``implicit lazy val system`` must be declared exactly like that (you can of
+course pass arguments to the actor system factory as needed) because trait
+:class:`TestKitBase` needs the system during its construction.
+
+.. warning::
+
+  Use of the trait is discouraged because of potential issues with binary
+  backwards compatibility in the future, use at own risk.
+
 Specs2
 ------