move code to src/test

* so that it compiles and tests pass
* fix some additional snip references in getting started

akka-docs/src/test/scala/docs/faq/Faq.scala

@@ -0,0 +1,30 @@
+package docs.faq
+
+import akka.actor.Actor
+
+//#exhaustiveness-check
+object MyActor {
+  // these are the messages we accept
+  sealed abstract trait Message
+  final case class FooMessage(foo: String) extends Message
+  final case class BarMessage(bar: Int) extends Message
+
+  // these are the replies we send
+  sealed abstract trait Reply
+  final case class BazMessage(baz: String) extends Reply
+}
+
+class MyActor extends Actor {
+  import MyActor._
+  def receive = {
+    case message: Message => message match {
+      case BarMessage(bar) => sender() ! BazMessage("Got " + bar)
+      // warning here: 
+      // "match may not be exhaustive. It would fail on the following input: FooMessage(_)"
+      //#exhaustiveness-check
+      case FooMessage(_)   => // avoid the warning in our build logs
+      //#exhaustiveness-check
+    }
+  }
+}
+//#exhaustiveness-check