Unit tests of Cluster, see 2163

* ClusterSpec
- Test gossiping rules for deputies and unreachable
- Fix strange/wrong probabilites for gossip to unreachable and deputy nodes
- Fix lost order of Members when using map (without .toSeq) on the members SortedSet

* MemberSpec
- Test equals, hashCode

* GossipSpec
- Test member merge by status prio
- Fix bug in member merge (groupBy was wrong)

akka-cluster/src/main/scala/akka/cluster/Cluster.scala

@@ -180,7 +180,7 @@ case class GossipOverview(
  */
 case class Gossip(
   overview: GossipOverview = GossipOverview(),
-  members: SortedSet[Member], // sorted set of members with their status, sorted by name
+  members: SortedSet[Member], // sorted set of members with their status, sorted by address
   meta: Map[String, Array[Byte]] = Map.empty[String, Array[Byte]],
   version: VectorClock = VectorClock()) // vector clock version
   extends ClusterMessage // is a serializable cluster message
@@ -214,12 +214,8 @@ case class Gossip(
     // 1. merge vector clocks
     val mergedVClock = this.version merge that.version
 
-    // 2. group all members by Address => Vector[Member]
+    // 2. group all members by Address => Seq[Member]
-    var membersGroupedByAddress = Map.empty[Address, Vector[Member]]
+    val membersGroupedByAddress = (this.members.toSeq ++ that.members.toSeq).groupBy(_.address)
-    (this.members ++ that.members) foreach { m ⇒
-      val ms = membersGroupedByAddress.get(m.address).getOrElse(Vector.empty[Member])
-      membersGroupedByAddress += (m.address -> (ms :+ m))
-    }
 
     // 3. merge members by selecting the single Member with highest MemberStatus out of the Member groups
     val mergedMembers =
@@ -252,10 +248,9 @@ case class Gossip(
  * Manages routing of the different cluster commands.
  * Instantiated as a single instance for each Cluster - e.g. commands are serialized to Cluster message after message.
  */
-final class ClusterCommandDaemon extends Actor {
+private[akka] final class ClusterCommandDaemon(cluster: Cluster) extends Actor {
   import ClusterAction._
 
-  val cluster = Cluster(context.system)
   val log = Logging(context.system, this)
 
   def receive = {
@@ -273,9 +268,8 @@ final class ClusterCommandDaemon extends Actor {
  * Pooled and routed with N number of configurable instances.
  * Concurrent access to Cluster.
  */
-final class ClusterGossipDaemon extends Actor {
+private[akka] final class ClusterGossipDaemon(cluster: Cluster) extends Actor {
   val log = Logging(context.system, this)
-  val cluster = Cluster(context.system)
 
   def receive = {
     case GossipEnvelope(sender, gossip) ⇒ cluster.receive(sender, gossip)
@@ -287,13 +281,13 @@ final class ClusterGossipDaemon extends Actor {
 /**
  * Supervisor managing the different Cluster daemons.
  */
-final class ClusterDaemonSupervisor extends Actor {
+private[akka] final class ClusterDaemonSupervisor(cluster: Cluster) extends Actor {
   val log = Logging(context.system, this)
-  val cluster = Cluster(context.system)
 
-  private val commands = context.actorOf(Props[ClusterCommandDaemon], "commands")
+  private val commands = context.actorOf(Props(new ClusterCommandDaemon(cluster)), "commands")
   private val gossip = context.actorOf(
-    Props[ClusterGossipDaemon].withRouter(RoundRobinRouter(cluster.clusterSettings.NrOfGossipDaemons)), "gossip")
+    Props(new ClusterGossipDaemon(cluster)).withRouter(
+      RoundRobinRouter(cluster.clusterSettings.NrOfGossipDaemons)), "gossip")
 
   def receive = Actor.emptyBehavior
 
@@ -396,7 +390,7 @@ class Cluster(system: ExtendedActorSystem) extends Extension { clusterNode ⇒
 
   // create superisor for daemons under path "/system/cluster"
   private val clusterDaemons = {
-    val createChild = CreateChild(Props[ClusterDaemonSupervisor], "cluster")
+    val createChild = CreateChild(Props(new ClusterDaemonSupervisor(this)), "cluster")
     Await.result(system.systemGuardian ? createChild, defaultTimeout.duration) match {
       case a: ActorRef  ⇒ a
       case e: Exception ⇒ throw e
@@ -794,9 +788,11 @@ class Cluster(system: ExtendedActorSystem) extends Extension { clusterNode ⇒
   }
 
   /**
+   * INTERNAL API
+   *
    * Gossips latest gossip to an address.
    */
-  private def gossipTo(address: Address): Unit = {
+  protected def gossipTo(address: Address): Unit = {
     val connection = clusterGossipConnectionFor(address)
     log.debug("Cluster Node [{}] - Gossiping to [{}]", selfAddress, connection)
     connection ! GossipEnvelope(self, latestGossip)
@@ -805,23 +801,43 @@ class Cluster(system: ExtendedActorSystem) extends Extension { clusterNode ⇒
   /**
    * Gossips latest gossip to a random member in the set of members passed in as argument.
    *
-   * @return 'true' if it gossiped to a "deputy" member.
+   * @return the used [[akka.actor.Address] if any
    */
-  private def gossipToRandomNodeOf(addresses: Iterable[Address]): Boolean = {
+  private def gossipToRandomNodeOf(addresses: IndexedSeq[Address]): Option[Address] = {
     log.debug("Cluster Node [{}] - Selecting random node to gossip to [{}]", selfAddress, addresses.mkString(", "))
-    if (addresses.isEmpty) false
+    val peers = addresses filterNot (_ == selfAddress) // filter out myself
-    else {
+    val peer = selectRandomNode(peers)
-      val peers = addresses filter (_ != selfAddress) // filter out myself
+    peer foreach gossipTo
-      val peer = selectRandomNode(peers)
+    peer
-      gossipTo(peer)
+  }
-      deputyNodes exists (peer == _)
+
+  /**
+   * INTERNAL API
+   */
+  protected[akka] def gossipToUnreachableProbablity(membersSize: Int, unreachableSize: Int): Double =
+    (membersSize + unreachableSize) match {
+      case 0   ⇒ 0.0
+      case sum ⇒ unreachableSize.toDouble / sum
+    }
+
+  /**
+   * INTERNAL API
+   */
+  protected[akka] def gossipToDeputyProbablity(membersSize: Int, unreachableSize: Int, nrOfDeputyNodes: Int): Double = {
+    if (nrOfDeputyNodes > membersSize) 1.0
+    else if (nrOfDeputyNodes == 0) 0.0
+    else (membersSize + unreachableSize) match {
+      case 0   ⇒ 0.0
+      case sum ⇒ (nrOfDeputyNodes + unreachableSize).toDouble / sum
     }
   }
 
   /**
+   * INTERNAL API
+   *
    * Initates a new round of gossip.
    */
-  private def gossip(): Unit = {
+  private[akka] def gossip(): Unit = {
     val localState = state.get
 
     if (isSingletonCluster(localState)) {
@@ -833,38 +849,42 @@ class Cluster(system: ExtendedActorSystem) extends Extension { clusterNode ⇒
       log.debug("Cluster Node [{}] - Initiating new round of gossip", selfAddress)
 
       val localGossip = localState.latestGossip
-      val localMembers = localGossip.members
+      // important to not accidentally use `map` of the SortedSet, since the original order is not preserved
+      val localMembers = localGossip.members.toIndexedSeq
       val localMembersSize = localMembers.size
+      val localMemberAddresses = localMembers map { _.address }
 
-      val localUnreachableMembers = localGossip.overview.unreachable
+      val localUnreachableMembers = localGossip.overview.unreachable.toIndexedSeq
       val localUnreachableSize = localUnreachableMembers.size
 
       // 1. gossip to alive members
-      val gossipedToDeputy = gossipToRandomNodeOf(localMembers map { _.address })
+      val gossipedToAlive = gossipToRandomNodeOf(localMemberAddresses)
 
       // 2. gossip to unreachable members
       if (localUnreachableSize > 0) {
-        val probability: Double = localUnreachableSize / (localMembersSize + 1)
+        val probability = gossipToUnreachableProbablity(localMembersSize, localUnreachableSize)
-        if (ThreadLocalRandom.current.nextDouble() < probability) gossipToRandomNodeOf(localUnreachableMembers.map(_.address))
+        if (ThreadLocalRandom.current.nextDouble() < probability)
+          gossipToRandomNodeOf(localUnreachableMembers.map(_.address))
       }
 
       // 3. gossip to a deputy nodes for facilitating partition healing
-      val deputies = deputyNodes
+      val deputies = deputyNodes(localMemberAddresses)
-      if ((!gossipedToDeputy || localMembersSize < 1) && deputies.nonEmpty) {
+      val alreadyGossipedToDeputy = gossipedToAlive.map(deputies.contains(_)).getOrElse(false)
-        if (localMembersSize == 0) gossipToRandomNodeOf(deputies)
+      if ((!alreadyGossipedToDeputy || localMembersSize < NrOfDeputyNodes) && deputies.nonEmpty) {
-        else {
+        val probability = gossipToDeputyProbablity(localMembersSize, localUnreachableSize, NrOfDeputyNodes)
-          val probability = 1.0 / localMembersSize + localUnreachableSize
+        if (ThreadLocalRandom.current.nextDouble() < probability)
-          if (ThreadLocalRandom.current.nextDouble() <= probability) gossipToRandomNodeOf(deputies)
+          gossipToRandomNodeOf(deputies)
-        }
       }
     }
   }
 
   /**
+   * INTERNAL API
+   *
    * Reaps the unreachable members (moves them to the 'unreachable' list in the cluster overview) according to the failure detector's verdict.
    */
   @tailrec
-  final private def reapUnreachableMembers(): Unit = {
+  final private[akka] def reapUnreachableMembers(): Unit = {
     val localState = state.get
 
     if (!isSingletonCluster(localState) && isAvailable(localState)) {
@@ -905,10 +925,12 @@ class Cluster(system: ExtendedActorSystem) extends Extension { clusterNode ⇒
   }
 
   /**
+   * INTERNAL API
+   *
    * Runs periodic leader actions, such as auto-downing unreachable nodes, assigning partitions etc.
    */
   @tailrec
-  final private def leaderActions(): Unit = {
+  final private[akka] def leaderActions(): Unit = {
     val localState = state.get
     val localGossip = localState.latestGossip
     val localMembers = localGossip.members
@@ -1082,11 +1104,17 @@ class Cluster(system: ExtendedActorSystem) extends Extension { clusterNode ⇒
   private def clusterGossipConnectionFor(address: Address): ActorRef = system.actorFor(RootActorPath(address) / "system" / "cluster" / "gossip")
 
   /**
-   * Gets an Iterable with the addresses of a all the 'deputy' nodes - excluding this node if part of the group.
+   * Gets the addresses of a all the 'deputy' nodes - excluding this node if part of the group.
    */
-  private def deputyNodes: Iterable[Address] = state.get.latestGossip.members.toIterable map (_.address) drop 1 take NrOfDeputyNodes filter (_ != selfAddress)
+  private def deputyNodes(addresses: IndexedSeq[Address]): IndexedSeq[Address] =
+    addresses drop 1 take NrOfDeputyNodes filterNot (_ == selfAddress)
 
-  private def selectRandomNode(addresses: Iterable[Address]): Address = addresses.toSeq(ThreadLocalRandom.current nextInt addresses.size)
+  /**
+   * INTERNAL API
+   */
+  protected def selectRandomNode(addresses: IndexedSeq[Address]): Option[Address] =
+    if (addresses.isEmpty) None
+    else Some(addresses(ThreadLocalRandom.current nextInt addresses.size))
 
   private def isSingletonCluster(currentState: State): Boolean = currentState.latestGossip.members.size == 1
 

akka-cluster/src/multi-jvm/scala/akka/cluster/MultiNodeClusterSpec.scala

@@ -20,6 +20,7 @@ object MultiNodeClusterSpec {
       leader-actions-interval           = 200 ms
       unreachable-nodes-reaper-interval = 200 ms
       periodic-tasks-initial-delay      = 300 ms
+      nr-of-deputy-nodes                = 2
     }
     akka.test {
       single-expect-default = 5 s

akka-cluster/src/test/scala/akka/cluster/ClusterSpec.scala

@@ -0,0 +1,232 @@
+/**
+ *  Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package akka.cluster
+
+import akka.testkit.AkkaSpec
+import akka.util.duration._
+import akka.util.Duration
+import akka.actor.ExtendedActorSystem
+import akka.actor.Address
+import java.util.concurrent.atomic.AtomicInteger
+import org.scalatest.BeforeAndAfter
+
+object ClusterSpec {
+  val config = """
+    akka.cluster {
+      auto-down                    = off
+      nr-of-deputy-nodes           = 3
+      periodic-tasks-initial-delay = 120 seconds // turn off scheduled tasks
+    }
+    akka.actor.provider = "akka.remote.RemoteActorRefProvider"
+    akka.remote.netty.port = 0
+    akka.loglevel = DEBUG
+    """
+
+  case class GossipTo(address: Address)
+}
+
+@org.junit.runner.RunWith(classOf[org.scalatest.junit.JUnitRunner])
+class ClusterSpec extends AkkaSpec(ClusterSpec.config) with BeforeAndAfter {
+  import ClusterSpec._
+
+  val deterministicRandom = new AtomicInteger
+
+  val cluster = new Cluster(system.asInstanceOf[ExtendedActorSystem]) {
+
+    override def selectRandomNode(addresses: IndexedSeq[Address]): Option[Address] = {
+      if (addresses.isEmpty) None
+      else Some(addresses.toSeq(deterministicRandom.getAndIncrement % addresses.size))
+    }
+
+    override def gossipTo(address: Address): Unit = {
+      if (address == self.address) {
+        super.gossipTo(address)
+      }
+      // represent the gossip with a message to be used in asserts
+      testActor ! GossipTo(address)
+    }
+
+    @volatile
+    var _gossipToUnreachableProbablity = 0.0
+
+    override def gossipToUnreachableProbablity(membersSize: Int, unreachableSize: Int): Double = {
+      if (_gossipToUnreachableProbablity < 0.0) super.gossipToUnreachableProbablity(membersSize, unreachableSize)
+      else _gossipToUnreachableProbablity
+    }
+
+    @volatile
+    var _gossipToDeputyProbablity = 0.0
+
+    override def gossipToDeputyProbablity(membersSize: Int, unreachableSize: Int, deputySize: Int): Double = {
+      if (_gossipToDeputyProbablity < 0.0) super.gossipToDeputyProbablity(membersSize, unreachableSize, deputySize)
+      else _gossipToDeputyProbablity
+    }
+
+    @volatile
+    var _unavailable: Set[Address] = Set.empty
+
+    override val failureDetector = new AccrualFailureDetector(
+      system, selfAddress, clusterSettings.FailureDetectorThreshold, clusterSettings.FailureDetectorMaxSampleSize) {
+
+      override def isAvailable(connection: Address): Boolean = {
+        if (_unavailable.contains(connection)) false
+        else super.isAvailable(connection)
+      }
+    }
+
+  }
+
+  val selfAddress = cluster.self.address
+  val addresses = IndexedSeq(
+    selfAddress,
+    Address("akka", system.name, selfAddress.host.get, selfAddress.port.get + 1),
+    Address("akka", system.name, selfAddress.host.get, selfAddress.port.get + 2),
+    Address("akka", system.name, selfAddress.host.get, selfAddress.port.get + 3),
+    Address("akka", system.name, selfAddress.host.get, selfAddress.port.get + 4),
+    Address("akka", system.name, selfAddress.host.get, selfAddress.port.get + 5))
+
+  def memberStatus(address: Address): Option[MemberStatus] =
+    cluster.latestGossip.members.collectFirst { case m if m.address == address ⇒ m.status }
+
+  before {
+    cluster._gossipToUnreachableProbablity = 0.0
+    cluster._gossipToDeputyProbablity = 0.0
+    cluster._unavailable = Set.empty
+    deterministicRandom.set(0)
+  }
+
+  "A Cluster" must {
+
+    "initially be singleton cluster and reach convergence after first gossip" in {
+      cluster.isSingletonCluster must be(true)
+      cluster.latestGossip.members.map(_.address) must be(Set(selfAddress))
+      memberStatus(selfAddress) must be(Some(MemberStatus.Joining))
+      cluster.convergence.isDefined must be(false)
+      cluster.gossip()
+      expectMsg(GossipTo(selfAddress))
+      awaitCond(cluster.convergence.isDefined)
+      memberStatus(selfAddress) must be(Some(MemberStatus.Joining))
+      cluster.leaderActions()
+      memberStatus(selfAddress) must be(Some(MemberStatus.Up))
+    }
+
+    "accept a joining node" in {
+      cluster.joining(addresses(1))
+      cluster.latestGossip.members.map(_.address) must be(Set(selfAddress, addresses(1)))
+      memberStatus(addresses(1)) must be(Some(MemberStatus.Joining))
+      // FIXME why is it still convergence immediately after joining?
+      //cluster.convergence.isDefined must be(false)
+    }
+
+    "accept a few more joining nodes" in {
+      for (a ← addresses.drop(2)) {
+        cluster.joining(a)
+        memberStatus(a) must be(Some(MemberStatus.Joining))
+      }
+      cluster.latestGossip.members.map(_.address) must be(addresses.toSet)
+    }
+
+    "order members by host and port" in {
+      // note the importance of using toSeq before map, otherwise it will not preserve the order
+      cluster.latestGossip.members.toSeq.map(_.address) must be(addresses.toSeq)
+    }
+
+    "gossip to random live node" in {
+      cluster.latestGossip.members
+      cluster.gossip()
+      cluster.gossip()
+      cluster.gossip()
+      cluster.gossip()
+
+      expectMsg(GossipTo(addresses(1)))
+      expectMsg(GossipTo(addresses(2)))
+      expectMsg(GossipTo(addresses(3)))
+      expectMsg(GossipTo(addresses(4)))
+
+      expectNoMsg(1 second)
+    }
+
+    "use certain probability for gossiping to unreachable node depending on the number of unreachable and live nodes" in {
+      cluster._gossipToUnreachableProbablity = -1.0 // use real impl
+      cluster.gossipToUnreachableProbablity(10, 1) must be < (cluster.gossipToUnreachableProbablity(9, 1))
+      cluster.gossipToUnreachableProbablity(10, 1) must be < (cluster.gossipToUnreachableProbablity(10, 2))
+      cluster.gossipToUnreachableProbablity(10, 5) must be < (cluster.gossipToUnreachableProbablity(10, 9))
+      cluster.gossipToUnreachableProbablity(0, 10) must be <= (1.0)
+      cluster.gossipToUnreachableProbablity(1, 10) must be <= (1.0)
+      cluster.gossipToUnreachableProbablity(10, 0) must be(0.0 plusOrMinus (0.0001))
+      cluster.gossipToUnreachableProbablity(0, 0) must be(0.0 plusOrMinus (0.0001))
+    }
+
+    "use certain probability for gossiping to deputy node depending on the number of unreachable and live nodes" in {
+      cluster._gossipToDeputyProbablity = -1.0 // use real impl
+      cluster.gossipToDeputyProbablity(10, 1, 2) must be < (cluster.gossipToDeputyProbablity(9, 1, 2))
+      cluster.gossipToDeputyProbablity(10, 1, 2) must be < (cluster.gossipToDeputyProbablity(10, 2, 2))
+      cluster.gossipToDeputyProbablity(10, 1, 2) must be < (cluster.gossipToDeputyProbablity(10, 2, 3))
+      cluster.gossipToDeputyProbablity(10, 5, 5) must be < (cluster.gossipToDeputyProbablity(10, 9, 5))
+      cluster.gossipToDeputyProbablity(0, 10, 0) must be <= (1.0)
+      cluster.gossipToDeputyProbablity(1, 10, 1) must be <= (1.0)
+      cluster.gossipToDeputyProbablity(10, 0, 0) must be(0.0 plusOrMinus (0.0001))
+      cluster.gossipToDeputyProbablity(0, 0, 0) must be(0.0 plusOrMinus (0.0001))
+      cluster.gossipToDeputyProbablity(4, 0, 4) must be(1.0 plusOrMinus (0.0001))
+      cluster.gossipToDeputyProbablity(3, 7, 4) must be(1.0 plusOrMinus (0.0001))
+    }
+
+    "gossip to duputy node" in {
+      cluster._gossipToDeputyProbablity = 1.0 // always
+
+      // we have configured 2 deputy nodes
+      cluster.gossip() // 1 is deputy
+      cluster.gossip() // 2 is deputy
+      cluster.gossip() // 3 is deputy
+      cluster.gossip() // 4 is not deputy, and therefore a deputy is also used
+
+      expectMsg(GossipTo(addresses(1)))
+      expectMsg(GossipTo(addresses(2)))
+      expectMsg(GossipTo(addresses(3)))
+      expectMsg(GossipTo(addresses(4)))
+      // and the extra gossip to deputy
+      expectMsgAnyOf(GossipTo(addresses(1)), GossipTo(addresses(2)), GossipTo(addresses(3)))
+
+      expectNoMsg(1 second)
+
+    }
+
+    "gossip to random unreachable node" in {
+      val dead = Set(addresses(1))
+      cluster._unavailable = dead
+      cluster._gossipToUnreachableProbablity = 1.0 // always
+
+      cluster.reapUnreachableMembers()
+      cluster.latestGossip.overview.unreachable.map(_.address) must be(dead)
+
+      cluster.gossip()
+
+      expectMsg(GossipTo(addresses(2))) // first available
+      expectMsg(GossipTo(addresses(1))) // the unavailable
+
+      expectNoMsg(1 second)
+    }
+
+    "gossip to random deputy node if number of live nodes is less than number of deputy nodes" in {
+      cluster._gossipToDeputyProbablity = -1.0 // real impl
+      // 0 and 2 still alive
+      val dead = Set(addresses(1), addresses(3), addresses(4), addresses(5))
+      cluster._unavailable = dead
+
+      cluster.reapUnreachableMembers()
+      cluster.latestGossip.overview.unreachable.map(_.address) must be(dead)
+
+      for (n ← 1 to 20) {
+        cluster.gossip()
+        expectMsg(GossipTo(addresses(2))) // the only available
+        // and always to one of the 3 deputies
+        expectMsgAnyOf(GossipTo(addresses(1)), GossipTo(addresses(2)), GossipTo(addresses(3)))
+      }
+
+      expectNoMsg(1 second)
+
+    }
+  }
+}

akka-cluster/src/test/scala/akka/cluster/GossipSpec.scala

@@ -0,0 +1,42 @@
+/**
+ *  Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package akka.cluster
+
+import org.scalatest.WordSpec
+import org.scalatest.matchers.MustMatchers
+import akka.actor.Address
+import scala.collection.immutable.SortedSet
+
+@org.junit.runner.RunWith(classOf[org.scalatest.junit.JUnitRunner])
+class GossipSpec extends WordSpec with MustMatchers {
+
+  "A Gossip" must {
+
+    "merge members by status priority" in {
+      import MemberStatus._
+      val a1 = Member(Address("akka", "sys", "a", 2552), Up)
+      val a2 = Member(Address("akka", "sys", "a", 2552), Joining)
+      val b1 = Member(Address("akka", "sys", "b", 2552), Up)
+      val b2 = Member(Address("akka", "sys", "b", 2552), Removed)
+      val c1 = Member(Address("akka", "sys", "c", 2552), Leaving)
+      val c2 = Member(Address("akka", "sys", "c", 2552), Up)
+      val d1 = Member(Address("akka", "sys", "d", 2552), Leaving)
+      val d2 = Member(Address("akka", "sys", "d", 2552), Removed)
+
+      val g1 = Gossip(members = SortedSet(a1, b1, c1, d1))
+      val g2 = Gossip(members = SortedSet(a2, b2, c2, d2))
+
+      val merged1 = g1 merge g2
+      merged1.members must be(SortedSet(a1, b2, c1, d2))
+      merged1.members.toSeq.map(_.status) must be(Seq(Up, Removed, Leaving, Removed))
+
+      val merged2 = g2 merge g1
+      merged2.members must be(SortedSet(a1, b2, c1, d2))
+      merged2.members.toSeq.map(_.status) must be(Seq(Up, Removed, Leaving, Removed))
+
+    }
+
+  }
+}

akka-cluster/src/test/scala/akka/cluster/MemberSpec.scala

@@ -8,6 +8,7 @@ import org.scalatest.WordSpec
 import org.scalatest.matchers.MustMatchers
 import akka.actor.Address
 import scala.util.Random
+import scala.collection.immutable.SortedSet
 
 @org.junit.runner.RunWith(classOf[org.scalatest.junit.JUnitRunner])
 class MemberSpec extends WordSpec with MustMatchers {
@@ -26,6 +27,19 @@ class MemberSpec extends WordSpec with MustMatchers {
       val expected = IndexedSeq(m1, m2, m3, m4, m5)
       val shuffled = Random.shuffle(expected)
       shuffled.sorted must be(expected)
+      (SortedSet.empty[Member] ++ shuffled).toIndexedSeq must be(expected)
+    }
+
+    "have stable equals and hashCode" in {
+      val m1 = Member(Address("akka", "sys1", "host1", 9000), MemberStatus.Joining)
+      val m2 = Member(Address("akka", "sys1", "host1", 9000), MemberStatus.Up)
+      val m3 = Member(Address("akka", "sys1", "host1", 10000), MemberStatus.Up)
+
+      m1 must be(m2)
+      m1.hashCode must be(m2.hashCode)
+
+      m3 must not be (m2)
+      m3 must not be (m1)
     }
   }
 }