opendaylight/md-sal/sal-distributed-datastore/src/test/java/org/opendaylight/controller/cluster/datastore/entityownership/DistributedEntityOwnershipIntegrationTest.java

   1 /*
   2  * Copyright (c) 2015 Brocade Communications Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.controller.cluster.datastore.entityownership;
   9
  10 import static org.junit.Assert.assertEquals;
  11 import static org.junit.Assert.assertTrue;
  12 import static org.mockito.AdditionalMatchers.or;
  13 import static org.mockito.Mockito.atMost;
  14 import static org.mockito.Mockito.doNothing;
  15 import static org.mockito.Mockito.reset;
  16 import static org.mockito.Mockito.timeout;
  17 import static org.mockito.Mockito.verify;
  18 import static org.opendaylight.controller.cluster.datastore.entityownership.AbstractEntityOwnershipTest.ownershipChange;
  19 import static org.opendaylight.controller.cluster.datastore.entityownership.DistributedEntityOwnershipService.ENTITY_OWNERSHIP_SHARD_NAME;
  20 import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.CANDIDATE_NAME_NODE_ID;
  21 import static org.opendaylight.controller.cluster.datastore.entityownership.EntityOwnersModel.entityPath;
  22 import akka.actor.Status.Failure;
  23 import akka.actor.Status.Success;
  24 import akka.testkit.JavaTestKit;
  25 import com.google.common.base.Function;
  26 import com.google.common.base.Optional;
  27 import com.google.common.base.Stopwatch;
  28 import com.google.common.util.concurrent.Uninterruptibles;
  29 import java.util.ArrayList;
  30 import java.util.Arrays;
  31 import java.util.Collection;
  32 import java.util.List;
  33 import java.util.concurrent.TimeUnit;
  34 import org.junit.After;
  35 import org.junit.Before;
  36 import org.junit.Test;
  37 import org.mockito.ArgumentCaptor;
  38 import org.mockito.Mock;
  39 import org.mockito.Mockito;
  40 import org.mockito.MockitoAnnotations;
  41 import org.opendaylight.controller.cluster.datastore.DatastoreContext;
  42 import org.opendaylight.controller.cluster.datastore.DistributedDataStore;
  43 import org.opendaylight.controller.cluster.datastore.MemberNode;
  44 import org.opendaylight.controller.cluster.datastore.entityownership.selectionstrategy.EntityOwnerSelectionStrategyConfig;
  45 import org.opendaylight.controller.cluster.datastore.messages.AddShardReplica;
  46 import org.opendaylight.controller.cluster.raft.utils.InMemoryJournal;
  47 import org.opendaylight.controller.cluster.raft.utils.InMemorySnapshotStore;
  48 import org.opendaylight.controller.md.cluster.datastore.model.SchemaContextHelper;
  49 import org.opendaylight.controller.md.sal.common.api.clustering.CandidateAlreadyRegisteredException;
  50 import org.opendaylight.controller.md.sal.common.api.clustering.Entity;
  51 import org.opendaylight.controller.md.sal.common.api.clustering.EntityOwnershipCandidateRegistration;
  52 import org.opendaylight.controller.md.sal.common.api.clustering.EntityOwnershipChange;
  53 import org.opendaylight.controller.md.sal.common.api.clustering.EntityOwnershipListener;
  54 import org.opendaylight.controller.md.sal.common.api.clustering.EntityOwnershipService;
  55 import org.opendaylight.controller.md.sal.common.api.clustering.EntityOwnershipState;
  56 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;
  57 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  58 import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
  59 import org.opendaylight.yangtools.yang.data.api.schema.MapNode;
  60 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  61 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  62
  63 /**
  64  * End-to-end integration tests for the entity ownership functionality.
  65  *
  66  * @author Thomas Pantelis
  67  */
  68 public class DistributedEntityOwnershipIntegrationTest {
  69     private static final String MODULE_SHARDS_CONFIG = "module-shards-default.conf";
  70     private static final String MODULE_SHARDS_MEMBER_1_CONFIG = "module-shards-default-member-1.conf";
  71     private static final String ENTITY_TYPE1 = "entityType1";
  72     private static final String ENTITY_TYPE2 = "entityType2";
  73     private static final Entity ENTITY1 = new Entity(ENTITY_TYPE1, "entity1");
  74     private static final Entity ENTITY1_2 = new Entity(ENTITY_TYPE2, "entity1");
  75     private static final Entity ENTITY2 = new Entity(ENTITY_TYPE1, "entity2");
  76     private static final Entity ENTITY3 = new Entity(ENTITY_TYPE1, "entity3");
  77     private static final Entity ENTITY4 = new Entity(ENTITY_TYPE1, "entity4");
  78     private static final SchemaContext SCHEMA_CONTEXT = SchemaContextHelper.entityOwners();
  79
  80     private final DatastoreContext.Builder leaderDatastoreContextBuilder =
  81             DatastoreContext.newBuilder().shardHeartbeatIntervalInMillis(100).shardElectionTimeoutFactor(5).
  82                     shardIsolatedLeaderCheckIntervalInMillis(1000000);
  83
  84     private final DatastoreContext.Builder followerDatastoreContextBuilder =
  85             DatastoreContext.newBuilder().shardHeartbeatIntervalInMillis(100).shardElectionTimeoutFactor(10000);
  86
  87     private final List<MemberNode> memberNodes = new ArrayList<>();
  88
  89     @Mock
  90     private EntityOwnershipListener leaderMockListener;
  91
  92     @Mock
  93     private EntityOwnershipListener leaderMockListener2;
  94
  95     @Mock
  96     private EntityOwnershipListener follower1MockListener;
  97
  98     @Mock
  99     private EntityOwnershipListener follower2MockListener;
 100
 101     @Before
 102     public void setUp() {
 103         MockitoAnnotations.initMocks(this);
 104         InMemoryJournal.clear();
 105         InMemorySnapshotStore.clear();
 106     }
 107
 108     @After
 109     public void tearDown() {
 110         for(MemberNode m: memberNodes) {
 111             m.cleanup();
 112         }
 113     }
 114
 115     private DistributedEntityOwnershipService newOwnershipService(DistributedDataStore datastore) {
 116         DistributedEntityOwnershipService service = new DistributedEntityOwnershipService(datastore,
 117                 EntityOwnerSelectionStrategyConfig.newBuilder().build());
 118         service.start();
 119         return service;
 120     }
 121
 122     @Test
 123     public void testFunctionalityWithThreeNodes() throws Exception {
 124         String name = "test";
 125         MemberNode leaderNode = MemberNode.builder(memberNodes).akkaConfig("Member1").testName(name ).
 126                 moduleShardsConfig(MODULE_SHARDS_CONFIG).schemaContext(SCHEMA_CONTEXT).createOperDatastore(false).
 127                 datastoreContextBuilder(leaderDatastoreContextBuilder).build();
 128
 129         MemberNode follower1Node = MemberNode.builder(memberNodes).akkaConfig("Member2").testName(name ).
 130                 moduleShardsConfig(MODULE_SHARDS_CONFIG).schemaContext(SCHEMA_CONTEXT).createOperDatastore(false).
 131                 datastoreContextBuilder(followerDatastoreContextBuilder).build();
 132
 133         MemberNode follower2Node = MemberNode.builder(memberNodes).akkaConfig("Member3").testName(name ).
 134                 moduleShardsConfig(MODULE_SHARDS_CONFIG).schemaContext(SCHEMA_CONTEXT).createOperDatastore(false).
 135                 datastoreContextBuilder(followerDatastoreContextBuilder).build();
 136
 137         DistributedDataStore leaderDistributedDataStore = leaderNode.configDataStore();
 138
 139         leaderDistributedDataStore.waitTillReady();
 140         follower1Node.configDataStore().waitTillReady();
 141         follower2Node.configDataStore().waitTillReady();
 142
 143         EntityOwnershipService leaderEntityOwnershipService = newOwnershipService(leaderDistributedDataStore);
 144         EntityOwnershipService follower1EntityOwnershipService = newOwnershipService(follower1Node.configDataStore());
 145         EntityOwnershipService follower2EntityOwnershipService = newOwnershipService(follower2Node.configDataStore());
 146
 147         leaderNode.kit().waitUntilLeader(leaderNode.configDataStore().getActorContext(), ENTITY_OWNERSHIP_SHARD_NAME);
 148
 149         leaderEntityOwnershipService.registerListener(ENTITY_TYPE1, leaderMockListener);
 150         leaderEntityOwnershipService.registerListener(ENTITY_TYPE2, leaderMockListener2);
 151         follower1EntityOwnershipService.registerListener(ENTITY_TYPE1, follower1MockListener);
 152
 153         // Register leader candidate for entity1 and verify it becomes owner
 154
 155         leaderEntityOwnershipService.registerCandidate(ENTITY1);
 156         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY1, false, true, true));
 157         verify(follower1MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY1, false, false, true));
 158         reset(leaderMockListener, follower1MockListener);
 159
 160         verifyGetOwnershipState(leaderEntityOwnershipService, ENTITY1, true, true);
 161         verifyGetOwnershipState(follower1EntityOwnershipService, ENTITY1, false, true);
 162
 163         // Register leader candidate for entity1_2 (same id, different type) and verify it becomes owner
 164
 165         leaderEntityOwnershipService.registerCandidate(ENTITY1_2);
 166         verify(leaderMockListener2, timeout(5000)).ownershipChanged(ownershipChange(ENTITY1_2, false, true, true));
 167         verify(leaderMockListener, timeout(300).never()).ownershipChanged(ownershipChange(ENTITY1_2));
 168         reset(leaderMockListener2);
 169
 170         // Register follower1 candidate for entity1 and verify it gets added but doesn't become owner
 171
 172         follower1EntityOwnershipService.registerCandidate(ENTITY1);
 173         verifyCandidates(leaderDistributedDataStore, ENTITY1, "member-1", "member-2");
 174         verifyOwner(leaderDistributedDataStore, ENTITY1, "member-1");
 175         verify(leaderMockListener, timeout(300).never()).ownershipChanged(ownershipChange(ENTITY1));
 176         verify(follower1MockListener, timeout(300).never()).ownershipChanged(ownershipChange(ENTITY1));
 177
 178         // Register follower1 candidate for entity2 and verify it becomes owner
 179
 180         EntityOwnershipCandidateRegistration follower1Entity2Reg = follower1EntityOwnershipService.registerCandidate(ENTITY2);
 181         verify(follower1MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, true, true));
 182         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, false, true));
 183         reset(leaderMockListener, follower1MockListener);
 184
 185         // Register follower2 candidate for entity2 and verify it gets added but doesn't become owner
 186
 187         follower2EntityOwnershipService.registerListener(ENTITY_TYPE1, follower2MockListener);
 188         follower2EntityOwnershipService.registerCandidate(ENTITY2);
 189         verifyCandidates(leaderDistributedDataStore, ENTITY2, "member-2", "member-3");
 190         verifyOwner(leaderDistributedDataStore, ENTITY2, "member-2");
 191
 192         // Unregister follower1 candidate for entity2 and verify follower2 becomes owner
 193
 194         follower1Entity2Reg.close();
 195         verifyCandidates(leaderDistributedDataStore, ENTITY2, "member-3");
 196         verifyOwner(leaderDistributedDataStore, ENTITY2, "member-3");
 197         verify(follower1MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, true, false, true));
 198         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, false, true));
 199
 200         // Depending on timing, follower2MockListener could get ownershipChanged with "false, false, true" if
 201         // if the original ownership change with "member-2 is replicated to follower2 after the listener is
 202         // registered.
 203         Uninterruptibles.sleepUninterruptibly(500, TimeUnit.MILLISECONDS);
 204         verify(follower2MockListener, atMost(1)).ownershipChanged(ownershipChange(ENTITY2, false, false, true));
 205         verify(follower2MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, true, true));
 206
 207         // Register follower1 candidate for entity3 and verify it becomes owner
 208
 209         follower1EntityOwnershipService.registerCandidate(ENTITY3);
 210         verifyOwner(leaderDistributedDataStore, ENTITY3, "member-2");
 211         verify(follower1MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY3, false, true, true));
 212         verify(follower2MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY3, false, false, true));
 213         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY3, false, false, true));
 214
 215         // Register follower2 candidate for entity4 and verify it becomes owner
 216
 217         follower2EntityOwnershipService.registerCandidate(ENTITY4);
 218         verifyOwner(leaderDistributedDataStore, ENTITY4, "member-3");
 219         verify(follower2MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY4, false, true, true));
 220         verify(follower1MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY4, false, false, true));
 221         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY4, false, false, true));
 222         reset(follower1MockListener, follower2MockListener);
 223
 224         // Register follower1 candidate for entity4 and verify it gets added but doesn't become owner
 225
 226         follower1EntityOwnershipService.registerCandidate(ENTITY4);
 227         verifyCandidates(leaderDistributedDataStore, ENTITY4, "member-3", "member-2");
 228         verifyOwner(leaderDistributedDataStore, ENTITY4, "member-3");
 229
 230         // Shutdown follower2 and verify it's owned entities (entity 2 & 4) get re-assigned
 231
 232         reset(leaderMockListener, follower1MockListener);
 233         follower2Node.cleanup();
 234
 235         verify(follower1MockListener, timeout(15000).times(2)).ownershipChanged(or(ownershipChange(ENTITY4, false, true, true),
 236                 ownershipChange(ENTITY2, false, false, false)));
 237         verify(leaderMockListener, timeout(15000).times(2)).ownershipChanged(or(ownershipChange(ENTITY4, false, false, true),
 238                 ownershipChange(ENTITY2, false, false, false)));
 239         verifyOwner(leaderDistributedDataStore, ENTITY2, ""); // no other candidate
 240
 241         // Register leader candidate for entity2 and verify it becomes owner
 242
 243         EntityOwnershipCandidateRegistration leaderEntity2Reg = leaderEntityOwnershipService.registerCandidate(ENTITY2);
 244         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, true, true));
 245         verifyOwner(leaderDistributedDataStore, ENTITY2, "member-1");
 246
 247         // Unregister leader candidate for entity2 and verify the owner is cleared
 248
 249         leaderEntity2Reg.close();
 250         verifyOwner(leaderDistributedDataStore, ENTITY2, "");
 251         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, true, false, false));
 252         verify(follower1MockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY2, false, false, false));
 253     }
 254
 255     /**
 256      * Reproduces bug <a href="https://bugs.opendaylight.org/show_bug.cgi?id=4554">4554</a>
 257      *
 258      * @throws CandidateAlreadyRegisteredException
 259      */
 260     @Test
 261     public void testCloseCandidateRegistrationInQuickSuccession() throws CandidateAlreadyRegisteredException {
 262         String name = "testCloseCandidateRegistrationInQuickSuccession";
 263         MemberNode leaderNode = MemberNode.builder(memberNodes).akkaConfig("Member1").testName(name ).
 264                 moduleShardsConfig(MODULE_SHARDS_CONFIG).schemaContext(SCHEMA_CONTEXT).createOperDatastore(false).
 265                 datastoreContextBuilder(leaderDatastoreContextBuilder).build();
 266
 267         MemberNode follower1Node = MemberNode.builder(memberNodes).akkaConfig("Member2").testName(name ).
 268                 moduleShardsConfig(MODULE_SHARDS_CONFIG).schemaContext(SCHEMA_CONTEXT).createOperDatastore(false).
 269                 datastoreContextBuilder(followerDatastoreContextBuilder).build();
 270
 271         MemberNode follower2Node = MemberNode.builder(memberNodes).akkaConfig("Member3").testName(name ).
 272                 moduleShardsConfig(MODULE_SHARDS_CONFIG).schemaContext(SCHEMA_CONTEXT).createOperDatastore(false).
 273                 datastoreContextBuilder(followerDatastoreContextBuilder).build();
 274
 275         DistributedDataStore leaderDistributedDataStore = leaderNode.configDataStore();
 276
 277         leaderDistributedDataStore.waitTillReady();
 278         follower1Node.configDataStore().waitTillReady();
 279         follower2Node.configDataStore().waitTillReady();
 280
 281         EntityOwnershipService leaderEntityOwnershipService = newOwnershipService(leaderDistributedDataStore);
 282         EntityOwnershipService follower1EntityOwnershipService = newOwnershipService(follower1Node.configDataStore());
 283         EntityOwnershipService follower2EntityOwnershipService = newOwnershipService(follower2Node.configDataStore());
 284
 285         leaderNode.kit().waitUntilLeader(leaderNode.configDataStore().getActorContext(), ENTITY_OWNERSHIP_SHARD_NAME);
 286
 287         leaderEntityOwnershipService.registerListener(ENTITY_TYPE1, leaderMockListener);
 288         follower1EntityOwnershipService.registerListener(ENTITY_TYPE1, follower1MockListener);
 289         follower2EntityOwnershipService.registerListener(ENTITY_TYPE1, follower2MockListener);
 290
 291         final EntityOwnershipCandidateRegistration candidate1 = leaderEntityOwnershipService.registerCandidate(ENTITY1);
 292         final EntityOwnershipCandidateRegistration candidate2 = follower1EntityOwnershipService.registerCandidate(ENTITY1);
 293         final EntityOwnershipCandidateRegistration candidate3 = follower2EntityOwnershipService.registerCandidate(ENTITY1);
 294
 295         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY1, false, true, true));
 296
 297         Mockito.reset(leaderMockListener);
 298
 299         candidate1.close();
 300         candidate2.close();
 301         candidate3.close();
 302
 303         ArgumentCaptor<EntityOwnershipChange> leaderChangeCaptor = ArgumentCaptor.forClass(EntityOwnershipChange.class);
 304         ArgumentCaptor<EntityOwnershipChange> follower1ChangeCaptor = ArgumentCaptor.forClass(EntityOwnershipChange.class);
 305         ArgumentCaptor<EntityOwnershipChange> follower2ChangeCaptor = ArgumentCaptor.forClass(EntityOwnershipChange.class);
 306         doNothing().when(leaderMockListener).ownershipChanged(leaderChangeCaptor.capture());
 307         doNothing().when(follower1MockListener).ownershipChanged(follower1ChangeCaptor.capture());
 308         doNothing().when(follower2MockListener).ownershipChanged(follower2ChangeCaptor.capture());
 309
 310         boolean passed = false;
 311         for(int i=0;i<100;i++) {
 312             Uninterruptibles.sleepUninterruptibly(50, TimeUnit.MILLISECONDS);
 313             if(!leaderEntityOwnershipService.getOwnershipState(ENTITY1).get().hasOwner() &&
 314                     !follower1EntityOwnershipService.getOwnershipState(ENTITY1).get().hasOwner() &&
 315                     !follower2EntityOwnershipService.getOwnershipState(ENTITY1).get().hasOwner() &&
 316                     leaderChangeCaptor.getAllValues().size() > 0 && !leaderChangeCaptor.getValue().hasOwner() &&
 317                     leaderChangeCaptor.getAllValues().size() > 0 && !follower1ChangeCaptor.getValue().hasOwner() &&
 318                     leaderChangeCaptor.getAllValues().size() > 0 && !follower2ChangeCaptor.getValue().hasOwner()) {
 319                 passed = true;
 320                 break;
 321             }
 322         }
 323
 324         assertTrue("No ownership change message was sent with hasOwner=false", passed);
 325     }
 326
 327     /**
 328      * Tests bootstrapping the entity-ownership shard when there's no shards initially configured for local
 329      * member. The entity-ownership shard is initially created as inactive (ie remains a follower), requiring
 330      * an AddShardReplica request to join it to an existing leader.
 331      */
 332     @Test
 333     public void testEntityOwnershipShardBootstrapping() throws Throwable {
 334         String name = "testEntityOwnershipShardBootstrapping";
 335         String moduleShardsConfig = MODULE_SHARDS_MEMBER_1_CONFIG;
 336         MemberNode leaderNode = MemberNode.builder(memberNodes).akkaConfig("Member1").testName(name ).
 337                 moduleShardsConfig(moduleShardsConfig).schemaContext(SCHEMA_CONTEXT).createOperDatastore(false).
 338                 datastoreContextBuilder(leaderDatastoreContextBuilder).build();
 339
 340         DistributedDataStore leaderDistributedDataStore = leaderNode.configDataStore();
 341         EntityOwnershipService leaderEntityOwnershipService = newOwnershipService(leaderDistributedDataStore);
 342
 343         leaderNode.kit().waitUntilLeader(leaderNode.configDataStore().getActorContext(), ENTITY_OWNERSHIP_SHARD_NAME);
 344
 345         MemberNode follower1Node = MemberNode.builder(memberNodes).akkaConfig("Member2").testName(name ).
 346                 moduleShardsConfig(moduleShardsConfig).schemaContext(SCHEMA_CONTEXT).createOperDatastore(false).
 347                 datastoreContextBuilder(followerDatastoreContextBuilder).build();
 348
 349         DistributedDataStore follower1DistributedDataStore = follower1Node.configDataStore();
 350         follower1DistributedDataStore.waitTillReady();
 351
 352         leaderNode.waitForMembersUp("member-2");
 353         follower1Node.waitForMembersUp("member-1");
 354
 355         EntityOwnershipService follower1EntityOwnershipService = newOwnershipService(follower1DistributedDataStore);
 356
 357         leaderEntityOwnershipService.registerListener(ENTITY_TYPE1, leaderMockListener);
 358
 359         // Register a candidate for follower1 - should get queued since follower1 has no leader
 360         EntityOwnershipCandidateRegistration candidateReg = follower1EntityOwnershipService.registerCandidate(ENTITY1);
 361         verify(leaderMockListener, timeout(300).never()).ownershipChanged(ownershipChange(ENTITY1));
 362
 363         // Add replica in follower1
 364         AddShardReplica addReplica = new AddShardReplica(ENTITY_OWNERSHIP_SHARD_NAME);
 365         follower1DistributedDataStore.getActorContext().getShardManager().tell(addReplica , follower1Node.kit().getRef());
 366         Object reply = follower1Node.kit().expectMsgAnyClassOf(JavaTestKit.duration("5 sec"), Success.class, Failure.class);
 367         if(reply instanceof Failure) {
 368             throw new AssertionError("AddShardReplica failed", ((Failure)reply).cause());
 369         }
 370
 371         // The queued candidate registration should proceed
 372         verify(leaderMockListener, timeout(5000)).ownershipChanged(ownershipChange(ENTITY1, false, false, true));
 373     }
 374
 375     private static void verifyGetOwnershipState(EntityOwnershipService service, Entity entity,
 376             boolean isOwner, boolean hasOwner) {
 377         Optional<EntityOwnershipState> state = service.getOwnershipState(entity);
 378         assertEquals("getOwnershipState present", true, state.isPresent());
 379         assertEquals("isOwner", isOwner, state.get().isOwner());
 380         assertEquals("hasOwner", hasOwner, state.get().hasOwner());
 381     }
 382
 383     private static void verifyCandidates(DistributedDataStore dataStore, Entity entity, String... expCandidates) throws Exception {
 384         AssertionError lastError = null;
 385         Stopwatch sw = Stopwatch.createStarted();
 386         while(sw.elapsed(TimeUnit.MILLISECONDS) <= 5000) {
 387             Optional<NormalizedNode<?, ?>> possible = dataStore.newReadOnlyTransaction().read(
 388                     entityPath(entity.getType(), entity.getId()).node(Candidate.QNAME)).get(5, TimeUnit.SECONDS);
 389             try {
 390                 assertEquals("Candidates not found for " + entity, true, possible.isPresent());
 391                 Collection<String> actual = new ArrayList<>();
 392                 for(MapEntryNode candidate: ((MapNode)possible.get()).getValue()) {
 393                     actual.add(candidate.getChild(CANDIDATE_NAME_NODE_ID).get().getValue().toString());
 394                 }
 395
 396                 assertEquals("Candidates for " + entity, Arrays.asList(expCandidates), actual);
 397                 return;
 398             } catch (AssertionError e) {
 399                 lastError = e;
 400                 Uninterruptibles.sleepUninterruptibly(300, TimeUnit.MILLISECONDS);
 401             }
 402         }
 403
 404         throw lastError;
 405     }
 406
 407     private static void verifyOwner(final DistributedDataStore dataStore, Entity entity, String expOwner) {
 408         AbstractEntityOwnershipTest.verifyOwner(expOwner, entity.getType(), entity.getId(),
 409                 new Function<YangInstanceIdentifier, NormalizedNode<?,?>>() {
 410                     @Override
 411                     public NormalizedNode<?, ?> apply(YangInstanceIdentifier path) {
 412                         try {
 413                             return dataStore.newReadOnlyTransaction().read(path).get(5, TimeUnit.SECONDS).get();
 414                         } catch (Exception e) {
 415                             return null;
 416                         }
 417                     }
 418                 });
 419     }
 420 }