Fix failure of testCloseCandidateRegistrationInQuickSuccession
[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / test / java / org / opendaylight / controller / cluster / datastore / entityownership / DistributedEntityOwnershipIntegrationTest.java
index ed7ca2d33e3ce5a0f79f4b4894a183ceaf722b6d..ecae2fa1d895f239946f647e4ba3ab30b736e3bc 100644 (file)
@@ -8,15 +8,22 @@
 package org.opendaylight.controller.cluster.datastore.entityownership;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.AdditionalMatchers.or;
+import static org.mockito.Mockito.atMost;
+import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.reset;
 import static org.mockito.Mockito.timeout;
 import static org.mockito.Mockito.verify;
 import static org.opendaylight.controller.cluster.datastore.entityownership.AbstractEntityOwnershipTest.ownershipChange;
+import static org.opendaylight.controller.cluster.datastore.entityownership.DistributedEntityOwnershipService.ENTITY_OWNERSHIP_SHARD_NAME;
 import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.CANDIDATE_NAME_NODE_ID;
 import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.entityPath;
 import akka.actor.ActorSystem;
 import akka.actor.Address;
 import akka.actor.AddressFromURIString;
+import akka.actor.Status.Failure;
+import akka.actor.Status.Success;
 import akka.cluster.Cluster;
 import akka.testkit.JavaTestKit;
 import com.google.common.base.Function;
@@ -31,14 +38,22 @@ import java.util.concurrent.TimeUnit;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
+import org.mockito.ArgumentCaptor;
 import org.mockito.Mock;
+import org.mockito.Mockito;
 import org.mockito.MockitoAnnotations;
 import org.opendaylight.controller.cluster.datastore.DatastoreContext;
 import org.opendaylight.controller.cluster.datastore.DistributedDataStore;
 import org.opendaylight.controller.cluster.datastore.IntegrationTestKit;
+import org.opendaylight.controller.cluster.datastore.entityownership.selectionstrategy.EntityOwnerSelectionStrategyConfig;
+import org.opendaylight.controller.cluster.datastore.messages.AddShardReplica;
 import org.opendaylight.controller.md.cluster.datastore.model.SchemaContextHelper;
+import org.opendaylight.controller.md.sal.common.api.clustering.CandidateAlreadyRegisteredException;
 import org.opendaylight.controller.md.sal.common.api.clustering.Entity;
-import org.opendaylight.controller.md.sal.common.api.clustering.EntityOwnershipCandidate;
+import org.opendaylight.controller.md.sal.common.api.clustering.EntityOwnershipCandidateRegistration;
+import org.opendaylight.controller.md.sal.common.api.clustering.EntityOwnershipChange;
+import org.opendaylight.controller.md.sal.common.api.clustering.EntityOwnershipListener;
+import org.opendaylight.controller.md.sal.common.api.clustering.EntityOwnershipState;
 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.md.sal.clustering.entity.owners.rev150804.entity.owners.entity.type.entity.Candidate;
 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
 import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
@@ -54,6 +69,7 @@ import org.opendaylight.yangtools.yang.model.api.SchemaContext;
 public class DistributedEntityOwnershipIntegrationTest {
     private static final Address MEMBER_1_ADDRESS = AddressFromURIString.parse("akka.tcp://cluster-test@127.0.0.1:2558");
     private static final String MODULE_SHARDS_CONFIG = "module-shards-default.conf";
+    private static final String MODULE_SHARDS_MEMBER_1_CONFIG = "module-shards-default-member-1.conf";
     private static final String ENTITY_TYPE1 = "entityType1";
     private static final String ENTITY_TYPE2 = "entityType2";
     private static final Entity ENTITY1 = new Entity(ENTITY_TYPE1, "entity1");
@@ -84,55 +100,62 @@ public class DistributedEntityOwnershipIntegrationTest {
     private IntegrationTestKit follower2TestKit;
 
     @Mock
-    private EntityOwnershipCandidate leaderMockCandidate;
+    private EntityOwnershipListener leaderMockListener;
 
     @Mock
-    private EntityOwnershipCandidate follower1MockCandidate;
+    private EntityOwnershipListener leaderMockListener2;
 
     @Mock
-    private EntityOwnershipCandidate follower2MockCandidate;
+    private EntityOwnershipListener follower1MockListener;
 
     @Mock
-    private EntityOwnershipCandidate leaderMockListener;
-
-    @Mock
-    private EntityOwnershipCandidate leaderMockListener2;
-
-    @Mock
-    private EntityOwnershipCandidate follower1MockListener;
-
-    @Mock
-    private EntityOwnershipCandidate follower2MockListener;
+    private EntityOwnershipListener follower2MockListener;
 
     @Before
     public void setUp() {
         MockitoAnnotations.initMocks(this);
+    }
 
-        leaderSystem = ActorSystem.create("cluster-test", ConfigFactory.load().getConfig("Member1"));
-        Cluster.get(leaderSystem).join(MEMBER_1_ADDRESS);
+    @After
+    public void tearDown() {
+        if(leaderSystem != null) {
+            JavaTestKit.shutdownActorSystem(leaderSystem);
+        }
 
-        follower1System = ActorSystem.create("cluster-test", ConfigFactory.load().getConfig("Member2"));
-        Cluster.get(follower1System).join(MEMBER_1_ADDRESS);
+        if(follower1System != null) {
+            JavaTestKit.shutdownActorSystem(follower1System);
+        }
+
+        if(follower2System != null) {
+            JavaTestKit.shutdownActorSystem(follower2System);
+        }
+    }
 
+    private void startAllSystems() {
+        startLeaderSystem();
+        startFollower1System();
+        startFollower2System();
+    }
+
+    private void startFollower2System() {
         follower2System = ActorSystem.create("cluster-test", ConfigFactory.load().getConfig("Member3"));
         Cluster.get(follower2System).join(MEMBER_1_ADDRESS);
     }
 
-    @After
-    public void tearDown() {
-        JavaTestKit.shutdownActorSystem(leaderSystem);
-        JavaTestKit.shutdownActorSystem(follower1System);
-        JavaTestKit.shutdownActorSystem(follower2System);
+    private void startFollower1System() {
+        follower1System = ActorSystem.create("cluster-test", ConfigFactory.load().getConfig("Member2"));
+        Cluster.get(follower1System).join(MEMBER_1_ADDRESS);
+    }
+
+    private void startLeaderSystem() {
+        leaderSystem = ActorSystem.create("cluster-test", ConfigFactory.load().getConfig("Member1"));
+        Cluster.get(leaderSystem).join(MEMBER_1_ADDRESS);
     }
 
     private void initDatastores(String type) {
-        leaderTestKit = new IntegrationTestKit(leaderSystem, leaderDatastoreContextBuilder);
-        leaderDistributedDataStore = leaderTestKit.setupDistributedDataStore(
-                type, MODULE_SHARDS_CONFIG, false, SCHEMA_CONTEXT);
+        initLeaderDatastore(type, MODULE_SHARDS_CONFIG);
 
-        follower1TestKit = new IntegrationTestKit(follower1System, followerDatastoreContextBuilder);
-        follower1DistributedDataStore = follower1TestKit.setupDistributedDataStore(
-                type, MODULE_SHARDS_CONFIG, false, SCHEMA_CONTEXT);
+        initFollower1Datastore(type, MODULE_SHARDS_CONFIG);
 
         follower2TestKit = new IntegrationTestKit(follower2System, followerDatastoreContextBuilder);
         follower2DistributedDataStore = follower2TestKit.setupDistributedDataStore(
@@ -142,21 +165,44 @@ public class DistributedEntityOwnershipIntegrationTest {
         follower1DistributedDataStore.waitTillReady();
         follower2DistributedDataStore.waitTillReady();
 
-        leaderEntityOwnershipService = new DistributedEntityOwnershipService(leaderDistributedDataStore);
-        leaderEntityOwnershipService.start();
+        startLeaderService();
 
-        follower1EntityOwnershipService = new DistributedEntityOwnershipService(follower1DistributedDataStore);
-        follower1EntityOwnershipService.start();
+        startFollower1Service();
 
-        follower2EntityOwnershipService = new DistributedEntityOwnershipService(follower2DistributedDataStore);
+        follower2EntityOwnershipService = new DistributedEntityOwnershipService(follower2DistributedDataStore,
+                EntityOwnerSelectionStrategyConfig.newBuilder().build());
         follower2EntityOwnershipService.start();
 
-        leaderTestKit.waitUntilLeader(leaderDistributedDataStore.getActorContext(),
-                DistributedEntityOwnershipService.ENTITY_OWNERSHIP_SHARD_NAME);
+        leaderTestKit.waitUntilLeader(leaderDistributedDataStore.getActorContext(), ENTITY_OWNERSHIP_SHARD_NAME);
+    }
+
+    private void startFollower1Service() {
+        follower1EntityOwnershipService = new DistributedEntityOwnershipService(follower1DistributedDataStore,
+                EntityOwnerSelectionStrategyConfig.newBuilder().build());
+        follower1EntityOwnershipService.start();
+    }
+
+    private void startLeaderService() {
+        leaderEntityOwnershipService = new DistributedEntityOwnershipService(leaderDistributedDataStore,
+                EntityOwnerSelectionStrategyConfig.newBuilder().build());
+        leaderEntityOwnershipService.start();
+    }
+
+    private void initFollower1Datastore(String type, String moduleConfig) {
+        follower1TestKit = new IntegrationTestKit(follower1System, followerDatastoreContextBuilder);
+        follower1DistributedDataStore = follower1TestKit.setupDistributedDataStore(
+                type, moduleConfig, false, SCHEMA_CONTEXT);
+    }
+
+    private void initLeaderDatastore(String type, String moduleConfig) {
+        leaderTestKit = new IntegrationTestKit(leaderSystem, leaderDatastoreContextBuilder);
+        leaderDistributedDataStore = leaderTestKit.setupDistributedDataStore(
+                type, moduleConfig, false, SCHEMA_CONTEXT);
     }
 
     @Test
     public void test() throws Exception {
+        startAllSystems();
         initDatastores("test");
 
         leaderEntityOwnershipService.registerListener(ENTITY_TYPE1, leaderMockListener);
@@ -165,21 +211,24 @@ public class DistributedEntityOwnershipIntegrationTest {
 
         // Register leader candidate for entity1 and verify it becomes owner
 
-        leaderEntityOwnershipService.registerCandidate(ENTITY1, leaderMockCandidate);
+        leaderEntityOwnershipService.registerCandidate(ENTITY1);
         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY1, false, true, true));
         verify(follower1MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY1, false, false, true));
         reset(leaderMockListener, follower1MockListener);
 
+        verifyGetOwnershipState(leaderEntityOwnershipService, ENTITY1, true, true);
+        verifyGetOwnershipState(follower1EntityOwnershipService, ENTITY1, false, true);
+
         // Register leader candidate for entity1_2 (same id, different type) and verify it becomes owner
 
-        leaderEntityOwnershipService.registerCandidate(ENTITY1_2, leaderMockCandidate);
+        leaderEntityOwnershipService.registerCandidate(ENTITY1_2);
         verify(leaderMockListener2, timeout(5000)).ownershipChanged(ownershipChange(ENTITY1_2, false, true, true));
         verify(leaderMockListener, timeout(300).never()).ownershipChanged(ownershipChange(ENTITY1_2));
         reset(leaderMockListener2);
 
         // Register follower1 candidate for entity1 and verify it gets added but doesn't become owner
 
-        follower1EntityOwnershipService.registerCandidate(ENTITY1, follower1MockCandidate);
+        follower1EntityOwnershipService.registerCandidate(ENTITY1);
         verifyCandidates(leaderDistributedDataStore, ENTITY1, "member-1", "member-2");
         verifyOwner(leaderDistributedDataStore, ENTITY1, "member-1");
         verify(leaderMockListener, timeout(300).never()).ownershipChanged(ownershipChange(ENTITY1));
@@ -187,30 +236,36 @@ public class DistributedEntityOwnershipIntegrationTest {
 
         // Register follower1 candidate for entity2 and verify it becomes owner
 
-        follower1EntityOwnershipService.registerCandidate(ENTITY2, follower1MockCandidate);
-        verify(follower1MockCandidate, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, true, true));
+        follower1EntityOwnershipService.registerCandidate(ENTITY2);
+        verify(follower1MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, true, true));
         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, false, true));
         reset(leaderMockListener, follower1MockListener);
 
         // Register follower2 candidate for entity2 and verify it gets added but doesn't become owner
 
         follower2EntityOwnershipService.registerListener(ENTITY_TYPE1, follower2MockListener);
-        follower2EntityOwnershipService.registerCandidate(ENTITY2, follower2MockCandidate);
+        follower2EntityOwnershipService.registerCandidate(ENTITY2);
         verifyCandidates(leaderDistributedDataStore, ENTITY2, "member-2", "member-3");
         verifyOwner(leaderDistributedDataStore, ENTITY2, "member-2");
 
         // Unregister follower1 candidate for entity2 and verify follower2 becomes owner
 
-        follower1EntityOwnershipService.unregisterCandidate(ENTITY2, follower1MockCandidate);
+        follower1EntityOwnershipService.unregisterCandidate(ENTITY2);
+        verifyCandidates(leaderDistributedDataStore, ENTITY2, "member-3");
         verifyOwner(leaderDistributedDataStore, ENTITY2, "member-3");
-        verify(follower2MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, true, true));
         verify(follower1MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, true, false, true));
         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, false, true));
-        verifyCandidates(leaderDistributedDataStore, ENTITY2, "member-3");
+
+        // Depending on timing, follower2MockListener could get ownershipChanged with "false, false, true" if
+        // if the original ownership change with "member-2 is replicated to follower2 after the listener is
+        // registered.
+        Uninterruptibles.sleepUninterruptibly(500, TimeUnit.MILLISECONDS);
+        verify(follower2MockListener, atMost(1)).ownershipChanged(ownershipChange(ENTITY2, false, false, true));
+        verify(follower2MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, true, true));
 
         // Register follower1 candidate for entity3 and verify it becomes owner
 
-        follower1EntityOwnershipService.registerCandidate(ENTITY3, follower1MockCandidate);
+        follower1EntityOwnershipService.registerCandidate(ENTITY3);
         verifyOwner(leaderDistributedDataStore, ENTITY3, "member-2");
         verify(follower1MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY3, false, true, true));
         verify(follower2MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY3, false, false, true));
@@ -218,17 +273,16 @@ public class DistributedEntityOwnershipIntegrationTest {
 
         // Register follower2 candidate for entity4 and verify it becomes owner
 
-        follower2EntityOwnershipService.registerCandidate(ENTITY4, follower2MockCandidate);
+        follower2EntityOwnershipService.registerCandidate(ENTITY4);
         verifyOwner(leaderDistributedDataStore, ENTITY4, "member-3");
         verify(follower2MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY4, false, true, true));
         verify(follower1MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY4, false, false, true));
         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY4, false, false, true));
-        reset(follower2MockListener);
+        reset(follower1MockListener, follower2MockListener);
 
         // Register follower1 candidate for entity4 and verify it gets added but doesn't become owner
 
-        reset(follower1MockCandidate);
-        follower1EntityOwnershipService.registerCandidate(ENTITY4, follower1MockCandidate);
+        follower1EntityOwnershipService.registerCandidate(ENTITY4);
         verifyCandidates(leaderDistributedDataStore, ENTITY4, "member-3", "member-2");
         verifyOwner(leaderDistributedDataStore, ENTITY4, "member-3");
 
@@ -237,26 +291,125 @@ public class DistributedEntityOwnershipIntegrationTest {
         reset(leaderMockListener, follower1MockListener);
         JavaTestKit.shutdownActorSystem(follower2System);
 
-        verify(follower1MockListener, timeout(15000)).ownershipChanged(ownershipChange(ENTITY4, false, true, true));
-        verify(leaderMockListener, timeout(15000)).ownershipChanged(ownershipChange(ENTITY4, false, false, true));
-        verify(leaderMockListener, timeout(15000)).ownershipChanged(ownershipChange(ENTITY2, false, false, false));
+        verify(follower1MockListener, timeout(15000).times(2)).ownershipChanged(or(ownershipChange(ENTITY4, false, true, true),
+                ownershipChange(ENTITY2, false, false, false)));
+        verify(leaderMockListener, timeout(15000).times(2)).ownershipChanged(or(ownershipChange(ENTITY4, false, false, true),
+                ownershipChange(ENTITY2, false, false, false)));
         verifyOwner(leaderDistributedDataStore, ENTITY2, ""); // no other candidate
 
         // Register leader candidate for entity2 and verify it becomes owner
 
-        leaderEntityOwnershipService.registerCandidate(ENTITY2, leaderMockCandidate);
+        leaderEntityOwnershipService.registerCandidate(ENTITY2);
         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, true, true));
         verifyOwner(leaderDistributedDataStore, ENTITY2, "member-1");
 
         // Unregister leader candidate for entity2 and verify the owner is cleared
 
-        leaderEntityOwnershipService.unregisterCandidate(ENTITY2, leaderMockCandidate);
+        leaderEntityOwnershipService.unregisterCandidate(ENTITY2);
         verifyOwner(leaderDistributedDataStore, ENTITY2, "");
         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, true, false, false));
         verify(follower1MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, false, false));
     }
 
-    private void verifyCandidates(DistributedDataStore dataStore, Entity entity, String... expCandidates) throws Exception {
+    /**
+     * Reproduces bug <a href="https://bugs.opendaylight.org/show_bug.cgi?id=4554">4554</a>
+     *
+     * @throws CandidateAlreadyRegisteredException
+     */
+    @Test
+    public void testCloseCandidateRegistrationInQuickSuccession() throws CandidateAlreadyRegisteredException {
+        startAllSystems();
+        initDatastores("testCloseCandidateRegistrationInQuickSuccession");
+
+        leaderEntityOwnershipService.registerListener(ENTITY_TYPE1, leaderMockListener);
+        follower1EntityOwnershipService.registerListener(ENTITY_TYPE1, follower1MockListener);
+        follower2EntityOwnershipService.registerListener(ENTITY_TYPE1, follower2MockListener);
+
+        final EntityOwnershipCandidateRegistration candidate1 = leaderEntityOwnershipService.registerCandidate(ENTITY1);
+        final EntityOwnershipCandidateRegistration candidate2 = follower1EntityOwnershipService.registerCandidate(ENTITY1);
+        final EntityOwnershipCandidateRegistration candidate3 = follower2EntityOwnershipService.registerCandidate(ENTITY1);
+
+        verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY1, false, true, true));
+
+        Mockito.reset(leaderMockListener);
+
+        candidate1.close();
+        candidate2.close();
+        candidate3.close();
+
+        ArgumentCaptor<EntityOwnershipChange> leaderChangeCaptor = ArgumentCaptor.forClass(EntityOwnershipChange.class);
+        ArgumentCaptor<EntityOwnershipChange> follower1ChangeCaptor = ArgumentCaptor.forClass(EntityOwnershipChange.class);
+        ArgumentCaptor<EntityOwnershipChange> follower2ChangeCaptor = ArgumentCaptor.forClass(EntityOwnershipChange.class);
+        doNothing().when(leaderMockListener).ownershipChanged(leaderChangeCaptor.capture());
+        doNothing().when(follower1MockListener).ownershipChanged(follower1ChangeCaptor.capture());
+        doNothing().when(follower2MockListener).ownershipChanged(follower2ChangeCaptor.capture());
+
+        boolean passed = false;
+        for(int i=0;i<100;i++) {
+            Uninterruptibles.sleepUninterruptibly(50, TimeUnit.MILLISECONDS);
+            if(!leaderEntityOwnershipService.getOwnershipState(ENTITY1).get().hasOwner() &&
+                    !follower1EntityOwnershipService.getOwnershipState(ENTITY1).get().hasOwner() &&
+                    !follower2EntityOwnershipService.getOwnershipState(ENTITY1).get().hasOwner() &&
+                    leaderChangeCaptor.getAllValues().size() > 0 && !leaderChangeCaptor.getValue().hasOwner() &&
+                    leaderChangeCaptor.getAllValues().size() > 0 && !follower1ChangeCaptor.getValue().hasOwner() &&
+                    leaderChangeCaptor.getAllValues().size() > 0 && !follower2ChangeCaptor.getValue().hasOwner()) {
+                passed = true;
+                break;
+            }
+        }
+
+        assertTrue("No ownership change message was sent with hasOwner=false", passed);
+    }
+
+    /**
+     * Tests bootstrapping the entity-ownership shard when there's no shards initially configured for local
+     * member. The entity-ownership shard is initially created as inactive (ie remains a follower), requiring
+     * an AddShardReplica request to join it to an existing leader.
+     */
+    @Test
+    public void testEntityOwnershipShardBootstrapping() throws Throwable {
+        startLeaderSystem();
+        startFollower1System();
+        String type = "testEntityOwnershipShardBootstrapping";
+        initLeaderDatastore(type, MODULE_SHARDS_MEMBER_1_CONFIG);
+        initFollower1Datastore(type, MODULE_SHARDS_MEMBER_1_CONFIG);
+
+        leaderDistributedDataStore.waitTillReady();
+        follower1DistributedDataStore.waitTillReady();
+
+        startLeaderService();
+        startFollower1Service();
+
+        leaderTestKit.waitUntilLeader(leaderDistributedDataStore.getActorContext(), ENTITY_OWNERSHIP_SHARD_NAME);
+
+        leaderEntityOwnershipService.registerListener(ENTITY_TYPE1, leaderMockListener);
+
+        // Register a candidate for follower1 - should get queued since follower1 has no leader
+        follower1EntityOwnershipService.registerCandidate(ENTITY1);
+        verify(leaderMockListener, timeout(300).never()).ownershipChanged(ownershipChange(ENTITY1));
+
+        // Add replica in follower1
+        AddShardReplica addReplica = new AddShardReplica(ENTITY_OWNERSHIP_SHARD_NAME);
+        follower1DistributedDataStore.getActorContext().getShardManager().tell(addReplica , follower1TestKit.getRef());
+        Object reply = follower1TestKit.expectMsgAnyClassOf(JavaTestKit.duration("5 sec"), Success.class, Failure.class);
+        if(reply instanceof Failure) {
+            throw ((Failure)reply).cause();
+        }
+
+        // The queued candidate registration should proceed
+        verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY1));
+
+    }
+
+    private static void verifyGetOwnershipState(DistributedEntityOwnershipService service, Entity entity,
+            boolean isOwner, boolean hasOwner) {
+        Optional<EntityOwnershipState> state = service.getOwnershipState(entity);
+        assertEquals("getOwnershipState present", true, state.isPresent());
+        assertEquals("isOwner", isOwner, state.get().isOwner());
+        assertEquals("hasOwner", hasOwner, state.get().hasOwner());
+    }
+
+    private static void verifyCandidates(DistributedDataStore dataStore, Entity entity, String... expCandidates) throws Exception {
         AssertionError lastError = null;
         Stopwatch sw = Stopwatch.createStarted();
         while(sw.elapsed(TimeUnit.MILLISECONDS) <= 5000) {
@@ -280,7 +433,7 @@ public class DistributedEntityOwnershipIntegrationTest {
         throw lastError;
     }
 
-    private void verifyOwner(final DistributedDataStore dataStore, Entity entity, String expOwner) throws Exception {
+    private static void verifyOwner(final DistributedDataStore dataStore, Entity entity, String expOwner) {
         AbstractEntityOwnershipTest.verifyOwner(expOwner, entity.getType(), entity.getId(),
                 new Function<YangInstanceIdentifier, NormalizedNode<?,?>>() {
                     @Override