diff --git a/akka-cluster/src/main/scala/akka/cluster/ClusterDaemon.scala b/akka-cluster/src/main/scala/akka/cluster/ClusterDaemon.scala
index cf50f8a54f..7bb523024f 100644
--- a/akka-cluster/src/main/scala/akka/cluster/ClusterDaemon.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/ClusterDaemon.scala
@@ -236,7 +236,8 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
   var gossipStats = GossipStats()
 
   var seedNodeProcess: Option[ActorRef] = None
-  var seedNodeProcessCounter = 0 // for unique names 
+  var seedNodeProcessCounter = 0 // for unique names
+  var leaderActionCounter = 0
 
   /**
    * Looks up and returns the remote cluster command connection for the specific address.
@@ -608,9 +609,6 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
     } else if (envelope.to != selfUniqueAddress) {
       logInfo("Ignoring received gossip intended for someone else, from [{}] to [{}]", from.address, envelope.to)
       Ignored
-    } else if (!remoteGossip.overview.reachability.isReachable(selfUniqueAddress)) {
-      logInfo("Ignoring received gossip with myself as unreachable, from [{}]", from.address)
-      Ignored
     } else if (!localGossip.overview.reachability.isReachable(selfUniqueAddress, from)) {
       logInfo("Ignoring received gossip from unreachable [{}] ", from)
       Ignored
@@ -758,8 +756,21 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
   def leaderActions(): Unit =
     if (latestGossip.isLeader(selfUniqueAddress)) {
       // only run the leader actions if we are the LEADER
-      if (latestGossip.convergence)
+      val firstNotice = 20
+      val periodicNotice = 60
+      if (latestGossip.convergence(selfUniqueAddress)) {
+        if (leaderActionCounter >= firstNotice)
+          logInfo("Leader can perform its duties again")
+        leaderActionCounter = 0
         leaderActionsOnConvergence()
+      } else {
+        leaderActionCounter += 1
+        if (leaderActionCounter == firstNotice || leaderActionCounter % periodicNotice == 0)
+          logInfo("Leader can currently not perform its duties, reachability status: [{}], member status: [{}]",
+            latestGossip.reachabilityExcludingDownedObservers,
+            latestGossip.members.map(m ⇒
+              s"${m.address} ${m.status} seen=${latestGossip.seenByNode(m.uniqueAddress)}").mkString(", "))
+      }
     }
 
   /**
@@ -956,7 +967,7 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
 
   def validNodeForGossip(node: UniqueAddress): Boolean =
     (node != selfUniqueAddress && latestGossip.hasMember(node) &&
-      latestGossip.overview.reachability.isReachable(node))
+      latestGossip.reachabilityExcludingDownedObservers.isReachable(node))
 
   def updateLatestGossip(newGossip: Gossip): Unit = {
     // Updating the vclock version for the changes
diff --git a/akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala b/akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala
index 78d3218939..367c4d1333 100644
--- a/akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala
@@ -222,12 +222,12 @@ object ClusterEvent {
   /**
    * INTERNAL API
    */
-  private[cluster] def diffUnreachable(oldGossip: Gossip, newGossip: Gossip): immutable.Seq[UnreachableMember] =
+  private[cluster] def diffUnreachable(oldGossip: Gossip, newGossip: Gossip, selfUniqueAddress: UniqueAddress): immutable.Seq[UnreachableMember] =
     if (newGossip eq oldGossip) Nil
     else {
       val oldUnreachableNodes = oldGossip.overview.reachability.allUnreachableOrTerminated
       (newGossip.overview.reachability.allUnreachableOrTerminated.collect {
-        case node if !oldUnreachableNodes.contains(node) ⇒
+        case node if !oldUnreachableNodes.contains(node) && node != selfUniqueAddress ⇒
           UnreachableMember(newGossip.member(node))
       })(collection.breakOut)
     }
@@ -235,11 +235,11 @@ object ClusterEvent {
   /**
    * INTERNAL API
    */
-  private[cluster] def diffReachable(oldGossip: Gossip, newGossip: Gossip): immutable.Seq[ReachableMember] =
+  private[cluster] def diffReachable(oldGossip: Gossip, newGossip: Gossip, selfUniqueAddress: UniqueAddress): immutable.Seq[ReachableMember] =
     if (newGossip eq oldGossip) Nil
     else {
       (oldGossip.overview.reachability.allUnreachable.collect {
-        case node if newGossip.hasMember(node) && newGossip.overview.reachability.isReachable(node) ⇒
+        case node if newGossip.hasMember(node) && newGossip.overview.reachability.isReachable(node) && node != selfUniqueAddress ⇒
           ReachableMember(newGossip.member(node))
       })(collection.breakOut)
 
@@ -291,12 +291,12 @@ object ClusterEvent {
   /**
    * INTERNAL API
    */
-  private[cluster] def diffSeen(oldGossip: Gossip, newGossip: Gossip): immutable.Seq[SeenChanged] =
+  private[cluster] def diffSeen(oldGossip: Gossip, newGossip: Gossip, selfUniqueAddress: UniqueAddress): immutable.Seq[SeenChanged] =
     if (newGossip eq oldGossip) Nil
     else {
-      val newConvergence = newGossip.convergence
+      val newConvergence = newGossip.convergence(selfUniqueAddress)
       val newSeenBy = newGossip.seenBy
-      if (newConvergence != oldGossip.convergence || newSeenBy != oldGossip.seenBy)
+      if (newConvergence != oldGossip.convergence(selfUniqueAddress) || newSeenBy != oldGossip.seenBy)
         List(SeenChanged(newConvergence, newSeenBy.map(_.address)))
       else Nil
     }
@@ -319,6 +319,7 @@ private[cluster] final class ClusterDomainEventPublisher extends Actor with Acto
   with RequiresMessageQueue[UnboundedMessageQueueSemantics] {
   import InternalClusterAction._
 
+  val selfUniqueAddress = Cluster(context.system).selfUniqueAddress
   var latestGossip: Gossip = Gossip.empty
 
   override def preRestart(reason: Throwable, message: Option[Any]) {
@@ -346,9 +347,12 @@ private[cluster] final class ClusterDomainEventPublisher extends Actor with Acto
    * to mimic what you would have seen if you were listening to the events.
    */
   def sendCurrentClusterState(receiver: ActorRef): Unit = {
+    val unreachable: Set[Member] = latestGossip.overview.reachability.allUnreachableOrTerminated.collect {
+      case node if node != selfUniqueAddress ⇒ latestGossip.member(node)
+    }
     val state = CurrentClusterState(
       members = latestGossip.members,
-      unreachable = latestGossip.overview.reachability.allUnreachableOrTerminated map latestGossip.member,
+      unreachable = unreachable,
       seenBy = latestGossip.seenBy.map(_.address),
       leader = latestGossip.leader.map(_.address),
       roleLeaderMap = latestGossip.allRoles.map(r ⇒ r -> latestGossip.roleLeader(r).map(_.address))(collection.breakOut))
@@ -384,12 +388,12 @@ private[cluster] final class ClusterDomainEventPublisher extends Actor with Acto
 
   def publishDiff(oldGossip: Gossip, newGossip: Gossip, pub: AnyRef ⇒ Unit): Unit = {
     diffMemberEvents(oldGossip, newGossip) foreach pub
-    diffUnreachable(oldGossip, newGossip) foreach pub
-    diffReachable(oldGossip, newGossip) foreach pub
+    diffUnreachable(oldGossip, newGossip, selfUniqueAddress) foreach pub
+    diffReachable(oldGossip, newGossip, selfUniqueAddress) foreach pub
     diffLeader(oldGossip, newGossip) foreach pub
     diffRolesLeader(oldGossip, newGossip) foreach pub
     // publish internal SeenState for testing purposes
-    diffSeen(oldGossip, newGossip) foreach pub
+    diffSeen(oldGossip, newGossip, selfUniqueAddress) foreach pub
     diffReachability(oldGossip, newGossip) foreach pub
   }
 
diff --git a/akka-cluster/src/main/scala/akka/cluster/Gossip.scala b/akka-cluster/src/main/scala/akka/cluster/Gossip.scala
index d5054f3978..313fad160f 100644
--- a/akka-cluster/src/main/scala/akka/cluster/Gossip.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/Gossip.scala
@@ -20,7 +20,7 @@ private[cluster] object Gossip {
     if (members.isEmpty) empty else empty.copy(members = members)
 
   private val leaderMemberStatus = Set[MemberStatus](Up, Leaving)
-  private val convergenceMemberStatus = Set[MemberStatus](Up, Leaving)
+  val convergenceMemberStatus = Set[MemberStatus](Up, Leaving) // FIXME private
   val convergenceSkipUnreachableWithMemberStatus = Set[MemberStatus](Down, Exiting)
   val removeUnreachableWithMemberStatus = Set[MemberStatus](Down, Exiting)
 
@@ -159,19 +159,26 @@ private[cluster] final case class Gossip(
    *
    * @return true if convergence have been reached and false if not
    */
-  def convergence: Boolean = {
+  def convergence(selfUniqueAddress: UniqueAddress): Boolean = {
     // First check that:
-    //   1. we don't have any members that are unreachable, or
+    //   1. we don't have any members that are unreachable, excluding observations from members
+    //      that have status DOWN, or
     //   2. all unreachable members in the set have status DOWN or EXITING
     // Else we can't continue to check for convergence
     // When that is done we check that all members with a convergence
-    // status is in the seen table and has the latest vector clock
-    // version
-    val unreachable = overview.reachability.allUnreachableOrTerminated map member
+    // status is in the seen table, i.e. has seen this version
+    val unreachable = reachabilityExcludingDownedObservers.allUnreachableOrTerminated.collect {
+      case node if (node != selfUniqueAddress) ⇒ member(node)
+    }
     unreachable.forall(m ⇒ Gossip.convergenceSkipUnreachableWithMemberStatus(m.status)) &&
       !members.exists(m ⇒ Gossip.convergenceMemberStatus(m.status) && !seenByNode(m.uniqueAddress))
   }
 
+  lazy val reachabilityExcludingDownedObservers: Reachability = {
+    val downed = members.collect { case m if m.status == Down ⇒ m }
+    overview.reachability.removeObservers(downed.map(_.uniqueAddress))
+  }
+
   def isLeader(node: UniqueAddress): Boolean = leader == Some(node)
 
   def leader: Option[UniqueAddress] = leaderOf(members)
diff --git a/akka-cluster/src/main/scala/akka/cluster/Reachability.scala b/akka-cluster/src/main/scala/akka/cluster/Reachability.scala
index 64211f488a..a3ba198045 100644
--- a/akka-cluster/src/main/scala/akka/cluster/Reachability.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/Reachability.scala
@@ -187,6 +187,18 @@ private[cluster] class Reachability private (
     }
   }
 
+  def removeObservers(nodes: Set[UniqueAddress]): Reachability =
+    if (nodes.isEmpty)
+      this
+    else {
+      val newRecords = records.filterNot(r ⇒ nodes(r.observer))
+      if (newRecords.size == records.size) this
+      else {
+        val newVersions = versions -- nodes
+        Reachability(newRecords, newVersions)
+      }
+    }
+
   def status(observer: UniqueAddress, subject: UniqueAddress): ReachabilityStatus =
     observerRows(observer) match {
       case None ⇒ Reachable
diff --git a/akka-cluster/src/test/scala/akka/cluster/ClusterDomainEventPublisherSpec.scala b/akka-cluster/src/test/scala/akka/cluster/ClusterDomainEventPublisherSpec.scala
index 1f24e401b1..de7a981606 100644
--- a/akka-cluster/src/test/scala/akka/cluster/ClusterDomainEventPublisherSpec.scala
+++ b/akka-cluster/src/test/scala/akka/cluster/ClusterDomainEventPublisherSpec.scala
@@ -19,8 +19,15 @@ import akka.testkit.ImplicitSender
 import akka.actor.ActorRef
 import akka.testkit.TestProbe
 
+object ClusterDomainEventPublisherSpec {
+  val config = """
+    akka.actor.provider = "akka.cluster.ClusterActorRefProvider"
+    akka.remote.netty.tcp.port = 0
+    """
+}
+
 @org.junit.runner.RunWith(classOf[org.scalatest.junit.JUnitRunner])
-class ClusterDomainEventPublisherSpec extends AkkaSpec
+class ClusterDomainEventPublisherSpec extends AkkaSpec(ClusterDomainEventPublisherSpec.config)
   with BeforeAndAfterEach with ImplicitSender {
 
   var publisher: ActorRef = _
diff --git a/akka-cluster/src/test/scala/akka/cluster/ClusterDomainEventSpec.scala b/akka-cluster/src/test/scala/akka/cluster/ClusterDomainEventSpec.scala
index efc86d6b55..204c4baecc 100644
--- a/akka-cluster/src/test/scala/akka/cluster/ClusterDomainEventSpec.scala
+++ b/akka-cluster/src/test/scala/akka/cluster/ClusterDomainEventSpec.scala
@@ -34,6 +34,7 @@ class ClusterDomainEventSpec extends WordSpec with Matchers {
   val eJoining = TestMember(Address("akka.tcp", "sys", "e", 2552), Joining, eRoles)
   val eUp = TestMember(Address("akka.tcp", "sys", "e", 2552), Up, eRoles)
   val eDown = TestMember(Address("akka.tcp", "sys", "e", 2552), Down, eRoles)
+  val selfDummyAddress = UniqueAddress(Address("akka.tcp", "sys", "selfDummy", 2552), 17)
 
   private[cluster] def converge(gossip: Gossip): (Gossip, Set[UniqueAddress]) =
     ((gossip, Set.empty[UniqueAddress]) /: gossip.members) { case ((gs, as), m) ⇒ (gs.seen(m.uniqueAddress), as + m.uniqueAddress) }
@@ -43,7 +44,7 @@ class ClusterDomainEventSpec extends WordSpec with Matchers {
     "be empty for the same gossip" in {
       val g1 = Gossip(members = SortedSet(aUp))
 
-      diffUnreachable(g1, g1) should be(Seq.empty)
+      diffUnreachable(g1, g1, selfDummyAddress) should be(Seq.empty)
     }
 
     "be produced for new members" in {
@@ -51,8 +52,8 @@ class ClusterDomainEventSpec extends WordSpec with Matchers {
       val (g2, s2) = converge(Gossip(members = SortedSet(aUp, bUp, eJoining)))
 
       diffMemberEvents(g1, g2) should be(Seq(MemberUp(bUp)))
-      diffUnreachable(g1, g2) should be(Seq.empty)
-      diffSeen(g1, g2) should be(Seq(SeenChanged(convergence = true, seenBy = s2.map(_.address))))
+      diffUnreachable(g1, g2, selfDummyAddress) should be(Seq.empty)
+      diffSeen(g1, g2, selfDummyAddress) should be(Seq(SeenChanged(convergence = true, seenBy = s2.map(_.address))))
     }
 
     "be produced for changed status of members" in {
@@ -60,8 +61,8 @@ class ClusterDomainEventSpec extends WordSpec with Matchers {
       val (g2, s2) = converge(Gossip(members = SortedSet(aUp, bUp, cLeaving, eJoining)))
 
       diffMemberEvents(g1, g2) should be(Seq(MemberUp(aUp)))
-      diffUnreachable(g1, g2) should be(Seq.empty)
-      diffSeen(g1, g2) should be(Seq(SeenChanged(convergence = true, seenBy = s2.map(_.address))))
+      diffUnreachable(g1, g2, selfDummyAddress) should be(Seq.empty)
+      diffSeen(g1, g2, selfDummyAddress) should be(Seq(SeenChanged(convergence = true, seenBy = s2.map(_.address))))
     }
 
     "be produced for members in unreachable" in {
@@ -73,8 +74,10 @@ class ClusterDomainEventSpec extends WordSpec with Matchers {
         unreachable(aUp.uniqueAddress, bDown.uniqueAddress)
       val g2 = Gossip(members = SortedSet(aUp, cUp, bDown, eDown), overview = GossipOverview(reachability = reachability2))
 
-      diffUnreachable(g1, g2) should be(Seq(UnreachableMember(bDown)))
-      diffSeen(g1, g2) should be(Seq.empty)
+      diffUnreachable(g1, g2, selfDummyAddress) should be(Seq(UnreachableMember(bDown)))
+      // never include self member in unreachable
+      diffUnreachable(g1, g2, bDown.uniqueAddress) should be(Seq())
+      diffSeen(g1, g2, selfDummyAddress) should be(Seq.empty)
     }
 
     "be produced for members becoming reachable after unreachable" in {
@@ -88,8 +91,12 @@ class ClusterDomainEventSpec extends WordSpec with Matchers {
         reachable(aUp.uniqueAddress, bUp.uniqueAddress)
       val g2 = Gossip(members = SortedSet(aUp, cUp, bUp, eUp), overview = GossipOverview(reachability = reachability2))
 
-      diffUnreachable(g1, g2) should be(Seq(UnreachableMember(cUp)))
-      diffReachable(g1, g2) should be(Seq(ReachableMember(bUp)))
+      diffUnreachable(g1, g2, selfDummyAddress) should be(Seq(UnreachableMember(cUp)))
+      // never include self member in unreachable
+      diffUnreachable(g1, g2, cUp.uniqueAddress) should be(Seq())
+      diffReachable(g1, g2, selfDummyAddress) should be(Seq(ReachableMember(bUp)))
+      // never include self member in reachable
+      diffReachable(g1, g2, bUp.uniqueAddress) should be(Seq())
     }
 
     "be produced for removed members" in {
@@ -97,8 +104,8 @@ class ClusterDomainEventSpec extends WordSpec with Matchers {
       val (g2, s2) = converge(Gossip(members = SortedSet(aUp)))
 
       diffMemberEvents(g1, g2) should be(Seq(MemberRemoved(dRemoved, Exiting)))
-      diffUnreachable(g1, g2) should be(Seq.empty)
-      diffSeen(g1, g2) should be(Seq(SeenChanged(convergence = true, seenBy = s2.map(_.address))))
+      diffUnreachable(g1, g2, selfDummyAddress) should be(Seq.empty)
+      diffSeen(g1, g2, selfDummyAddress) should be(Seq(SeenChanged(convergence = true, seenBy = s2.map(_.address))))
     }
 
     "be produced for convergence changes" in {
@@ -106,11 +113,11 @@ class ClusterDomainEventSpec extends WordSpec with Matchers {
       val g2 = Gossip(members = SortedSet(aUp, bUp, eJoining)).seen(aUp.uniqueAddress).seen(bUp.uniqueAddress)
 
       diffMemberEvents(g1, g2) should be(Seq.empty)
-      diffUnreachable(g1, g2) should be(Seq.empty)
-      diffSeen(g1, g2) should be(Seq(SeenChanged(convergence = true, seenBy = Set(aUp.address, bUp.address))))
+      diffUnreachable(g1, g2, selfDummyAddress) should be(Seq.empty)
+      diffSeen(g1, g2, selfDummyAddress) should be(Seq(SeenChanged(convergence = true, seenBy = Set(aUp.address, bUp.address))))
       diffMemberEvents(g2, g1) should be(Seq.empty)
-      diffUnreachable(g2, g1) should be(Seq.empty)
-      diffSeen(g2, g1) should be(Seq(SeenChanged(convergence = true, seenBy = Set(aUp.address, bUp.address, eJoining.address))))
+      diffUnreachable(g2, g1, selfDummyAddress) should be(Seq.empty)
+      diffSeen(g2, g1, selfDummyAddress) should be(Seq(SeenChanged(convergence = true, seenBy = Set(aUp.address, bUp.address, eJoining.address))))
     }
 
     "be produced for leader changes" in {
@@ -118,8 +125,8 @@ class ClusterDomainEventSpec extends WordSpec with Matchers {
       val (g2, s2) = converge(Gossip(members = SortedSet(bUp, eJoining)))
 
       diffMemberEvents(g1, g2) should be(Seq(MemberRemoved(aRemoved, Up)))
-      diffUnreachable(g1, g2) should be(Seq.empty)
-      diffSeen(g1, g2) should be(Seq(SeenChanged(convergence = true, seenBy = s2.map(_.address))))
+      diffUnreachable(g1, g2, selfDummyAddress) should be(Seq.empty)
+      diffSeen(g1, g2, selfDummyAddress) should be(Seq(SeenChanged(convergence = true, seenBy = s2.map(_.address))))
       diffLeader(g1, g2) should be(Seq(LeaderChanged(Some(bUp.address))))
     }
 
diff --git a/akka-cluster/src/test/scala/akka/cluster/GossipSpec.scala b/akka-cluster/src/test/scala/akka/cluster/GossipSpec.scala
index 4de5e17d1a..9f4f61517b 100644
--- a/akka-cluster/src/test/scala/akka/cluster/GossipSpec.scala
+++ b/akka-cluster/src/test/scala/akka/cluster/GossipSpec.scala
@@ -29,7 +29,51 @@ class GossipSpec extends WordSpec with Matchers {
   "A Gossip" must {
 
     "reach convergence when it's empty" in {
-      Gossip.empty.convergence should be(true)
+      Gossip.empty.convergence(a1.uniqueAddress) should be(true)
+    }
+
+    "reach convergence for one node" in {
+      val g1 = (Gossip(members = SortedSet(a1))).seen(a1.uniqueAddress)
+      g1.convergence(a1.uniqueAddress) should be(true)
+    }
+
+    "not reach convergence until all have seen version" in {
+      val g1 = (Gossip(members = SortedSet(a1, b1))).seen(a1.uniqueAddress)
+      g1.convergence(a1.uniqueAddress) should be(false)
+    }
+
+    "reach convergence for two nodes" in {
+      val g1 = (Gossip(members = SortedSet(a1, b1))).seen(a1.uniqueAddress).seen(b1.uniqueAddress)
+      g1.convergence(a1.uniqueAddress) should be(true)
+    }
+
+    "reach convergence, skipping joining" in {
+      // e1 is joining
+      val g1 = (Gossip(members = SortedSet(a1, b1, e1))).seen(a1.uniqueAddress).seen(b1.uniqueAddress)
+      g1.convergence(a1.uniqueAddress) should be(true)
+    }
+
+    "reach convergence, skipping down" in {
+      // e3 is down
+      val g1 = (Gossip(members = SortedSet(a1, b1, e3))).seen(a1.uniqueAddress).seen(b1.uniqueAddress)
+      g1.convergence(a1.uniqueAddress) should be(true)
+    }
+
+    "not reach convergence when unreachable" in {
+      val r1 = Reachability.empty.unreachable(b1.uniqueAddress, a1.uniqueAddress)
+      val g1 = (Gossip(members = SortedSet(a1, b1), overview = GossipOverview(reachability = r1)))
+        .seen(a1.uniqueAddress).seen(b1.uniqueAddress)
+      g1.convergence(b1.uniqueAddress) should be(false)
+      // but from a1's point of view (it knows that itself is not unreachable)
+      g1.convergence(a1.uniqueAddress) should be(true)
+    }
+
+    "reach convergence when downed node has observed unreachable" in {
+      // e3 is Down
+      val r1 = Reachability.empty.unreachable(e3.uniqueAddress, a1.uniqueAddress)
+      val g1 = (Gossip(members = SortedSet(a1, b1, e3), overview = GossipOverview(reachability = r1)))
+        .seen(a1.uniqueAddress).seen(b1.uniqueAddress).seen(e3.uniqueAddress)
+      g1.convergence(b1.uniqueAddress) should be(true)
     }
 
     "merge members by status priority" in {
diff --git a/akka-cluster/src/test/scala/akka/cluster/ReachabilitySpec.scala b/akka-cluster/src/test/scala/akka/cluster/ReachabilitySpec.scala
index f7bc4de786..8b10f8fe61 100644
--- a/akka-cluster/src/test/scala/akka/cluster/ReachabilitySpec.scala
+++ b/akka-cluster/src/test/scala/akka/cluster/ReachabilitySpec.scala
@@ -64,6 +64,19 @@ class ReachabilitySpec extends WordSpec with Matchers {
       r.isReachable(nodeA) should be(true)
     }
 
+    "exclude observations from specific (downed) nodes" in {
+      val r = Reachability.empty.
+        unreachable(nodeC, nodeA).reachable(nodeC, nodeA).
+        unreachable(nodeC, nodeB).
+        unreachable(nodeB, nodeA).unreachable(nodeB, nodeC)
+
+      r.isReachable(nodeA) should be(false)
+      r.isReachable(nodeB) should be(false)
+      r.isReachable(nodeC) should be(false)
+      r.allUnreachableOrTerminated should be(Set(nodeA, nodeB, nodeC))
+      r.removeObservers(Set(nodeB)).allUnreachableOrTerminated should be(Set(nodeB))
+    }
+
     "be pruned when all records of an observer are Reachable" in {
       val r = Reachability.empty.
         unreachable(nodeB, nodeA).unreachable(nodeB, nodeC).