[TEST} make sure unicast bw comp test uses specifically set transport port and properly configure unicast hosts

Added also assertBusy block needed since we test the local cluster state on each node, not only on the master node.

src/test/java/org/elasticsearch/bwcompat/UnicastBackwardsCompatibilityTest.java

@@ -34,8 +34,9 @@ public class UnicastBackwardsCompatibilityTest extends ElasticsearchBackwardsCom
     @Override
     protected Settings nodeSettings(int nodeOrdinal) {
         return ImmutableSettings.builder()
+                .put("transport.tcp.port", 9380 + nodeOrdinal)
                 .put("discovery.zen.ping.multicast.enabled", false)
-                .put("discovery.zen.ping.unicast.hosts", "localhost")
+                .put("discovery.zen.ping.unicast.hosts", "localhost:9390")
                 .put(super.nodeSettings(nodeOrdinal))
                 .build();
     }
@@ -44,22 +45,28 @@ public class UnicastBackwardsCompatibilityTest extends ElasticsearchBackwardsCom
     protected Settings externalNodeSettings(int nodeOrdinal) {
         return ImmutableSettings.settingsBuilder()
                 .put("discovery.zen.ping.multicast.enabled", false)
-                .put("discovery.zen.ping.unicast.hosts", "localhost")
+                .put("transport.tcp.port", 9390 + nodeOrdinal)
+                .put("discovery.zen.ping.unicast.hosts", "localhost:9380")
                 .put(super.nodeSettings(nodeOrdinal))
                 .build();
     }
 
     @Test
-    public void testUnicastDiscovery() {
-        for (Client client : clients()) {
-            ClusterState state = client.admin().cluster().prepareState().setLocal(true).get().getState();
-            int dataNodes = 0;
-            for (DiscoveryNode discoveryNode : state.nodes()) {
-                if (discoveryNode.isDataNode()) {
-                    dataNodes++;
-                }
-            }
-            assertThat(dataNodes, equalTo(cluster().numDataNodes()));
+    public void testUnicastDiscovery() throws Exception {
+        for (final Client client : clients()) {
+            assertBusy(new Runnable() {
+                           @Override
+                           public void run() {
+                               ClusterState state = client.admin().cluster().prepareState().setLocal(true).get().getState();
+                               int dataNodes = 0;
+                               for (DiscoveryNode discoveryNode : state.nodes()) {
+                                   if (discoveryNode.isDataNode()) {
+                                       dataNodes++;
+                                   }
+                               }
+                               assertThat(dataNodes, equalTo(cluster().numDataNodes()));
+                           }
+                       });
         }
     }
 }