wierd akka fsm matching problem

gistfile1.scala

import org.specs2.mutable.Specification
import akka.actor.Actor
import akka.actor.FSM
import akka.testkit.TestFSMRef
import org.specs2.specification.Scope

class AkkaFSMEventSpec extends Specification {

  case class A(msg: String)
  case class B(msg: String)
  
  class TestFSM extends Actor with FSM[Int, String] {
    startWith(1, "foo")
    when(1) { case Event(_, data) => stay() }
    initialize
    
    def event(message: Any) = Event(message, stateData)
    
    def evThenEv: PartialFunction[Event, Any] = {
      case Ev(A(msg)) => msg
      case Ev(B(msg)) => msg
    }
    
    def eventThenEv: PartialFunction[Event, Any] = {
      case Event(A(msg), data) => msg
      case Ev(B(msg)) => msg
    }
    
    def evThenEvent: PartialFunction[Event, Any] = {
      case Ev(B(msg)) => msg
      case Event(A(msg), data) => msg
    }
  }
  
  trait Fixture extends Scope {
    val fsm = TestFSMRef(new TestFSM()).underlyingActor
  }
  
  "Akka FSM" should {
    "match Ev then Ev" in new Fixture {
      fsm.evThenEv(fsm.event(B("msg"))) must_== "msg"
    }
    
    "match Event then Ev" in new Fixture {
      fsm.eventThenEv(fsm.event(B("msg"))) must_== "msg"
    }
    
    "match Ev then Event" in new Fixture {
      fsm.evThenEvent(fsm.event(B("msg"))) must_== "msg"
    }
  }
}