opendaylight/md-sal/sal-distributed-datastore/src/test/java/org/opendaylight/controller/cluster/datastore/AbstractShardTest.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;
   9
  10 import static org.junit.Assert.assertEquals;
  11 import static org.junit.Assert.assertNotNull;
  12 import static org.junit.Assert.assertTrue;
  13 import static org.junit.Assert.fail;
  14 import static org.mockito.Matchers.any;
  15 import static org.mockito.Mockito.doAnswer;
  16 import static org.mockito.Mockito.doReturn;
  17 import static org.mockito.Mockito.mock;
  18 import static org.opendaylight.controller.cluster.datastore.DataStoreVersions.CURRENT_VERSION;
  19 import static org.opendaylight.controller.cluster.datastore.ShardDataTreeMocking.successfulCanCommit;
  20 import static org.opendaylight.controller.cluster.datastore.ShardDataTreeMocking.successfulCommit;
  21 import static org.opendaylight.controller.cluster.datastore.ShardDataTreeMocking.successfulPreCommit;
  22
  23 import akka.actor.ActorRef;
  24 import akka.actor.PoisonPill;
  25 import akka.actor.Props;
  26 import akka.dispatch.Dispatchers;
  27 import akka.japi.Creator;
  28 import akka.pattern.Patterns;
  29 import akka.testkit.TestActorRef;
  30 import akka.util.Timeout;
  31 import com.google.common.base.Optional;
  32 import com.google.common.primitives.UnsignedLong;
  33 import com.google.common.util.concurrent.FutureCallback;
  34 import com.google.common.util.concurrent.Uninterruptibles;
  35 import java.io.IOException;
  36 import java.util.Collections;
  37 import java.util.HashMap;
  38 import java.util.Map;
  39 import java.util.Set;
  40 import java.util.concurrent.CountDownLatch;
  41 import java.util.concurrent.ExecutionException;
  42 import java.util.concurrent.TimeUnit;
  43 import java.util.concurrent.TimeoutException;
  44 import java.util.concurrent.atomic.AtomicInteger;
  45 import org.junit.After;
  46 import org.junit.Assert;
  47 import org.junit.Before;
  48 import org.opendaylight.controller.cluster.access.concepts.MemberName;
  49 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
  50 import org.opendaylight.controller.cluster.datastore.DatastoreContext.Builder;
  51 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
  52 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  53 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  54 import org.opendaylight.controller.cluster.datastore.modification.MergeModification;
  55 import org.opendaylight.controller.cluster.datastore.modification.MutableCompositeModification;
  56 import org.opendaylight.controller.cluster.datastore.modification.WriteModification;
  57 import org.opendaylight.controller.cluster.datastore.persisted.CommitTransactionPayload;
  58 import org.opendaylight.controller.cluster.datastore.persisted.PreBoronShardDataTreeSnapshot;
  59 import org.opendaylight.controller.cluster.datastore.persisted.ShardSnapshotState;
  60 import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry;
  61 import org.opendaylight.controller.cluster.raft.TestActorFactory;
  62 import org.opendaylight.controller.cluster.raft.persisted.Snapshot;
  63 import org.opendaylight.controller.cluster.raft.utils.InMemoryJournal;
  64 import org.opendaylight.controller.cluster.raft.utils.InMemorySnapshotStore;
  65 import org.opendaylight.controller.md.cluster.datastore.model.CarsModel;
  66 import org.opendaylight.controller.md.cluster.datastore.model.TestModel;
  67 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  68 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
  69 import org.opendaylight.yangtools.yang.data.api.schema.DataContainerChild;
  70 import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
  71 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  72 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTree;
  73 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  74 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidateNode;
  75 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidateTip;
  76 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification;
  77 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException;
  78 import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType;
  79 import org.opendaylight.yangtools.yang.data.api.schema.tree.TipProducingDataTree;
  80 import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType;
  81 import org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNodes;
  82 import org.opendaylight.yangtools.yang.data.impl.schema.tree.InMemoryDataTreeFactory;
  83 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
  84 import scala.concurrent.Await;
  85 import scala.concurrent.Future;
  86 import scala.concurrent.duration.Duration;
  87
  88 /**
  89  * Abstract base for shard unit tests.
  90  *
  91  * @author Thomas Pantelis
  92  */
  93 public abstract class AbstractShardTest extends AbstractActorTest {
  94     protected static final SchemaContext SCHEMA_CONTEXT = TestModel.createTestContext();
  95
  96     private static final AtomicInteger NEXT_SHARD_NUM = new AtomicInteger();
  97
  98     protected static final int HEARTBEAT_MILLIS = 100;
  99
 100     protected final ShardIdentifier shardID = ShardIdentifier.create("inventory", MemberName.forName("member-1"),
 101         "config" + NEXT_SHARD_NUM.getAndIncrement());
 102
 103     protected final Builder dataStoreContextBuilder = DatastoreContext.newBuilder()
 104             .shardJournalRecoveryLogBatchSize(3).shardSnapshotBatchCount(5000)
 105             .shardHeartbeatIntervalInMillis(HEARTBEAT_MILLIS);
 106
 107     protected final TestActorFactory actorFactory = new TestActorFactory(getSystem());
 108
 109     @Before
 110     public void setUp() {
 111         InMemorySnapshotStore.clear();
 112         InMemoryJournal.clear();
 113     }
 114
 115     @After
 116     public void tearDown() {
 117         InMemorySnapshotStore.clear();
 118         InMemoryJournal.clear();
 119         actorFactory.close();
 120     }
 121
 122     protected DatastoreContext newDatastoreContext() {
 123         return dataStoreContextBuilder.build();
 124     }
 125
 126     protected Props newShardProps() {
 127         return newShardBuilder().props();
 128     }
 129
 130     protected Shard.Builder newShardBuilder() {
 131         return Shard.builder().id(shardID).datastoreContext(newDatastoreContext())
 132             .schemaContextProvider(() -> SCHEMA_CONTEXT);
 133     }
 134
 135     protected void testRecovery(final Set<Integer> listEntryKeys) throws Exception {
 136         // Create the actor and wait for recovery complete.
 137
 138         final int nListEntries = listEntryKeys.size();
 139
 140         final CountDownLatch recoveryComplete = new CountDownLatch(1);
 141
 142         final Creator<Shard> creator = () -> new Shard(newShardBuilder()) {
 143             @Override
 144             protected void onRecoveryComplete() {
 145                 try {
 146                     super.onRecoveryComplete();
 147                 } finally {
 148                     recoveryComplete.countDown();
 149                 }
 150             }
 151         };
 152
 153         final TestActorRef<Shard> shard = TestActorRef.create(getSystem(),
 154                 Props.create(new DelegatingShardCreator(creator)).withDispatcher(Dispatchers.DefaultDispatcherId()),
 155                 "testRecovery");
 156
 157         assertEquals("Recovery complete", true, recoveryComplete.await(5, TimeUnit.SECONDS));
 158
 159         // Verify data in the data store.
 160
 161         final NormalizedNode<?, ?> outerList = readStore(shard, TestModel.OUTER_LIST_PATH);
 162         assertNotNull(TestModel.OUTER_LIST_QNAME.getLocalName() + " not found", outerList);
 163         assertTrue(TestModel.OUTER_LIST_QNAME.getLocalName() + " value is not Iterable",
 164                 outerList.getValue() instanceof Iterable);
 165         for (final Object entry: (Iterable<?>) outerList.getValue()) {
 166             assertTrue(TestModel.OUTER_LIST_QNAME.getLocalName() + " entry is not MapEntryNode",
 167                     entry instanceof MapEntryNode);
 168             final MapEntryNode mapEntry = (MapEntryNode)entry;
 169             final Optional<DataContainerChild<? extends PathArgument, ?>> idLeaf =
 170                     mapEntry.getChild(new YangInstanceIdentifier.NodeIdentifier(TestModel.ID_QNAME));
 171             assertTrue("Missing leaf " + TestModel.ID_QNAME.getLocalName(), idLeaf.isPresent());
 172             final Object value = idLeaf.get().getValue();
 173             assertTrue("Unexpected value for leaf " + TestModel.ID_QNAME.getLocalName() + ": " + value,
 174                     listEntryKeys.remove(value));
 175         }
 176
 177         if (!listEntryKeys.isEmpty()) {
 178             fail("Missing " + TestModel.OUTER_LIST_QNAME.getLocalName() + " entries with keys: " + listEntryKeys);
 179         }
 180
 181         assertEquals("Last log index", nListEntries,
 182                 shard.underlyingActor().getShardMBean().getLastLogIndex());
 183         assertEquals("Commit index", nListEntries,
 184                 shard.underlyingActor().getShardMBean().getCommitIndex());
 185         assertEquals("Last applied", nListEntries,
 186                 shard.underlyingActor().getShardMBean().getLastApplied());
 187
 188         shard.tell(PoisonPill.getInstance(), ActorRef.noSender());
 189     }
 190
 191     protected void verifyLastApplied(final TestActorRef<Shard> shard, final long expectedValue) {
 192         long lastApplied = -1;
 193         for (int i = 0; i < 20 * 5; i++) {
 194             lastApplied = shard.underlyingActor().getShardMBean().getLastApplied();
 195             if (lastApplied == expectedValue) {
 196                 return;
 197             }
 198             Uninterruptibles.sleepUninterruptibly(50, TimeUnit.MILLISECONDS);
 199         }
 200
 201         Assert.fail(String.format("Expected last applied: %d, Actual: %d", expectedValue, lastApplied));
 202     }
 203
 204     protected TipProducingDataTree createDelegatingMockDataTree() throws Exception {
 205         TipProducingDataTree actual = InMemoryDataTreeFactory.getInstance().create(TreeType.CONFIGURATION);
 206         final TipProducingDataTree mock = mock(TipProducingDataTree.class);
 207
 208         doAnswer(invocation -> {
 209             actual.validate(invocation.getArgumentAt(0, DataTreeModification.class));
 210             return null;
 211         }).when(mock).validate(any(DataTreeModification.class));
 212
 213         doAnswer(invocation -> {
 214             return actual.prepare(invocation.getArgumentAt(0, DataTreeModification.class));
 215         }).when(mock).prepare(any(DataTreeModification.class));
 216
 217         doAnswer(invocation -> {
 218             actual.commit(invocation.getArgumentAt(0, DataTreeCandidate.class));
 219             return null;
 220         }).when(mock).commit(any(DataTreeCandidate.class));
 221
 222         doAnswer(invocation -> {
 223             actual.setSchemaContext(invocation.getArgumentAt(0, SchemaContext.class));
 224             return null;
 225         }).when(mock).setSchemaContext(any(SchemaContext.class));
 226
 227         doAnswer(invocation -> {
 228             return actual.takeSnapshot();
 229         }).when(mock).takeSnapshot();
 230
 231         doAnswer(invocation -> {
 232             return actual.getRootPath();
 233         }).when(mock).getRootPath();
 234
 235         return mock;
 236     }
 237
 238     protected ShardDataTreeCohort mockShardDataTreeCohort() {
 239         ShardDataTreeCohort cohort = mock(ShardDataTreeCohort.class);
 240         DataTreeCandidate candidate = mockCandidate("candidate");
 241         successfulCanCommit(cohort);
 242         successfulPreCommit(cohort, candidate);
 243         successfulCommit(cohort);
 244         doReturn(candidate).when(cohort).getCandidate();
 245         return cohort;
 246     }
 247
 248     protected Map<TransactionIdentifier, CapturingShardDataTreeCohort> setupCohortDecorator(final Shard shard,
 249             final TransactionIdentifier... transactionIDs) {
 250         final Map<TransactionIdentifier, CapturingShardDataTreeCohort> cohortMap = new HashMap<>();
 251         for (TransactionIdentifier id: transactionIDs) {
 252             cohortMap.put(id, new CapturingShardDataTreeCohort());
 253         }
 254
 255         shard.getCommitCoordinator().setCohortDecorator((transactionID, actual) -> {
 256             CapturingShardDataTreeCohort cohort = cohortMap.get(transactionID);
 257             cohort.setDelegate(actual);
 258             return cohort;
 259         });
 260
 261         return cohortMap;
 262     }
 263
 264     protected BatchedModifications prepareBatchedModifications(final TransactionIdentifier transactionID,
 265                                                                final MutableCompositeModification modification) {
 266         return prepareBatchedModifications(transactionID, modification, false);
 267     }
 268
 269     protected static BatchedModifications prepareBatchedModifications(final TransactionIdentifier transactionID,
 270                                                              final MutableCompositeModification modification,
 271                                                              final boolean doCommitOnReady) {
 272         final BatchedModifications batchedModifications = new BatchedModifications(transactionID, CURRENT_VERSION);
 273         batchedModifications.addModification(modification);
 274         batchedModifications.setReady(true);
 275         batchedModifications.setDoCommitOnReady(doCommitOnReady);
 276         batchedModifications.setTotalMessagesSent(1);
 277         return batchedModifications;
 278     }
 279
 280     protected static BatchedModifications prepareBatchedModifications(final TransactionIdentifier transactionID,
 281             final YangInstanceIdentifier path, final NormalizedNode<?, ?> data, final boolean doCommitOnReady) {
 282         final MutableCompositeModification modification = new MutableCompositeModification();
 283         modification.addModification(new WriteModification(path, data));
 284         return prepareBatchedModifications(transactionID, modification, doCommitOnReady);
 285     }
 286
 287     protected static ForwardedReadyTransaction prepareForwardedReadyTransaction(final TestActorRef<Shard> shard,
 288             final TransactionIdentifier transactionID, final YangInstanceIdentifier path,
 289             final NormalizedNode<?, ?> data, final boolean doCommitOnReady) {
 290         ReadWriteShardDataTreeTransaction rwTx = shard.underlyingActor().getDataStore()
 291                 .newReadWriteTransaction(transactionID);
 292         rwTx.getSnapshot().write(path, data);
 293         return new ForwardedReadyTransaction(transactionID, CURRENT_VERSION, rwTx, doCommitOnReady);
 294     }
 295
 296     public static NormalizedNode<?,?> readStore(final TestActorRef<? extends Shard> shard,
 297             final YangInstanceIdentifier id) throws ExecutionException, InterruptedException {
 298         return shard.underlyingActor().getDataStore().readNode(id).orNull();
 299     }
 300
 301     public static NormalizedNode<?,?> readStore(final DataTree store, final YangInstanceIdentifier id) {
 302         return store.takeSnapshot().readNode(id).orNull();
 303     }
 304
 305     public void writeToStore(final TestActorRef<Shard> shard, final YangInstanceIdentifier id,
 306             final NormalizedNode<?,?> node) throws InterruptedException, ExecutionException {
 307         Future<Object> future = Patterns.ask(shard, newBatchedModifications(nextTransactionId(),
 308                 id, node, true, true, 1), new Timeout(5, TimeUnit.SECONDS));
 309         try {
 310             Await.ready(future, Duration.create(5, TimeUnit.SECONDS));
 311         } catch (TimeoutException e) {
 312             throw new ExecutionException(e);
 313         }
 314     }
 315
 316     public static void writeToStore(final ShardDataTree store, final YangInstanceIdentifier id,
 317             final NormalizedNode<?,?> node) throws Exception {
 318         BatchedModifications batched = newBatchedModifications(nextTransactionId(), id, node, true, true, 1);
 319         DataTreeModification modification = store.getDataTree().takeSnapshot().newModification();
 320         batched.apply(modification);
 321         store.notifyListeners(store.commit(modification));
 322     }
 323
 324     public static void writeToStore(final DataTree store, final YangInstanceIdentifier id,
 325             final NormalizedNode<?,?> node) throws DataValidationFailedException {
 326         final DataTreeModification transaction = store.takeSnapshot().newModification();
 327
 328         transaction.write(id, node);
 329         transaction.ready();
 330         store.validate(transaction);
 331         final DataTreeCandidate candidate = store.prepare(transaction);
 332         store.commit(candidate);
 333     }
 334
 335     public void mergeToStore(final ShardDataTree store, final YangInstanceIdentifier id,
 336             final NormalizedNode<?,?> node) throws Exception {
 337         final BatchedModifications batched = new BatchedModifications(nextTransactionId(), CURRENT_VERSION);
 338         batched.addModification(new MergeModification(id, node));
 339         batched.setReady(true);
 340         batched.setDoCommitOnReady(true);
 341         batched.setTotalMessagesSent(1);
 342
 343         DataTreeModification modification = store.getDataTree().takeSnapshot().newModification();
 344         batched.apply(modification);
 345         store.notifyListeners(store.commit(modification));
 346     }
 347
 348     DataTree setupInMemorySnapshotStore() throws DataValidationFailedException {
 349         final DataTree testStore = InMemoryDataTreeFactory.getInstance().create(TreeType.OPERATIONAL);
 350         testStore.setSchemaContext(SCHEMA_CONTEXT);
 351
 352         writeToStore(testStore, TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
 353
 354         final NormalizedNode<?, ?> root = readStore(testStore, YangInstanceIdentifier.EMPTY);
 355
 356         InMemorySnapshotStore.addSnapshot(shardID.toString(), Snapshot.create(
 357                 new ShardSnapshotState(new PreBoronShardDataTreeSnapshot(root)),
 358                 Collections.<ReplicatedLogEntry>emptyList(), 0, 1, -1, -1, 1, null, null));
 359         return testStore;
 360     }
 361
 362     static CommitTransactionPayload payloadForModification(final DataTree source, final DataTreeModification mod,
 363             final TransactionIdentifier transactionId) throws DataValidationFailedException, IOException {
 364         source.validate(mod);
 365         final DataTreeCandidate candidate = source.prepare(mod);
 366         source.commit(candidate);
 367         return CommitTransactionPayload.create(transactionId, candidate);
 368     }
 369
 370     static BatchedModifications newBatchedModifications(final TransactionIdentifier transactionID,
 371             final YangInstanceIdentifier path, final NormalizedNode<?, ?> data, final boolean ready,
 372             final boolean doCommitOnReady, final int messagesSent) {
 373         final BatchedModifications batched = new BatchedModifications(transactionID, CURRENT_VERSION);
 374         batched.addModification(new WriteModification(path, data));
 375         batched.setReady(ready);
 376         batched.setDoCommitOnReady(doCommitOnReady);
 377         batched.setTotalMessagesSent(messagesSent);
 378         return batched;
 379     }
 380
 381     @SuppressWarnings("unchecked")
 382     static void verifyOuterListEntry(final TestActorRef<Shard> shard, final Object expIDValue) throws Exception {
 383         final NormalizedNode<?, ?> outerList = readStore(shard, TestModel.OUTER_LIST_PATH);
 384         assertNotNull(TestModel.OUTER_LIST_QNAME.getLocalName() + " not found", outerList);
 385         assertTrue(TestModel.OUTER_LIST_QNAME.getLocalName() + " value is not Iterable",
 386                 outerList.getValue() instanceof Iterable);
 387         final Object entry = ((Iterable<Object>)outerList.getValue()).iterator().next();
 388         assertTrue(TestModel.OUTER_LIST_QNAME.getLocalName() + " entry is not MapEntryNode",
 389                 entry instanceof MapEntryNode);
 390         final MapEntryNode mapEntry = (MapEntryNode)entry;
 391         final Optional<DataContainerChild<? extends PathArgument, ?>> idLeaf =
 392                 mapEntry.getChild(new YangInstanceIdentifier.NodeIdentifier(TestModel.ID_QNAME));
 393         assertTrue("Missing leaf " + TestModel.ID_QNAME.getLocalName(), idLeaf.isPresent());
 394         assertEquals(TestModel.ID_QNAME.getLocalName() + " value", expIDValue, idLeaf.get().getValue());
 395     }
 396
 397     public static DataTreeCandidateTip mockCandidate(final String name) {
 398         final DataTreeCandidateTip mockCandidate = mock(DataTreeCandidateTip.class, name);
 399         final DataTreeCandidateNode mockCandidateNode = mock(DataTreeCandidateNode.class, name + "-node");
 400         doReturn(ModificationType.WRITE).when(mockCandidateNode).getModificationType();
 401         doReturn(Optional.of(ImmutableNodes.containerNode(CarsModel.CARS_QNAME)))
 402                 .when(mockCandidateNode).getDataAfter();
 403         doReturn(CarsModel.BASE_PATH).when(mockCandidate).getRootPath();
 404         doReturn(mockCandidateNode).when(mockCandidate).getRootNode();
 405         return mockCandidate;
 406     }
 407
 408     static DataTreeCandidateTip mockUnmodifiedCandidate(final String name) {
 409         final DataTreeCandidateTip mockCandidate = mock(DataTreeCandidateTip.class, name);
 410         final DataTreeCandidateNode mockCandidateNode = mock(DataTreeCandidateNode.class, name + "-node");
 411         doReturn(ModificationType.UNMODIFIED).when(mockCandidateNode).getModificationType();
 412         doReturn(YangInstanceIdentifier.EMPTY).when(mockCandidate).getRootPath();
 413         doReturn(mockCandidateNode).when(mockCandidate).getRootNode();
 414         return mockCandidate;
 415     }
 416
 417     static void commitTransaction(final DataTree store, final DataTreeModification modification)
 418             throws DataValidationFailedException {
 419         modification.ready();
 420         store.validate(modification);
 421         store.commit(store.prepare(modification));
 422     }
 423
 424     @SuppressWarnings("serial")
 425     public static final class DelegatingShardCreator implements Creator<Shard> {
 426         private final Creator<Shard> delegate;
 427
 428         DelegatingShardCreator(final Creator<Shard> delegate) {
 429             this.delegate = delegate;
 430         }
 431
 432         @Override
 433         public Shard create() throws Exception {
 434             return delegate.create();
 435         }
 436     }
 437
 438     public static class CapturingShardDataTreeCohort extends ShardDataTreeCohort {
 439         private volatile ShardDataTreeCohort delegate;
 440         private FutureCallback<Void> canCommit;
 441         private FutureCallback<DataTreeCandidate> preCommit;
 442         private FutureCallback<UnsignedLong> commit;
 443
 444         public void setDelegate(final ShardDataTreeCohort delegate) {
 445             this.delegate = delegate;
 446         }
 447
 448         public FutureCallback<Void> getCanCommit() {
 449             assertNotNull("canCommit was not invoked", canCommit);
 450             return canCommit;
 451         }
 452
 453         public FutureCallback<DataTreeCandidate> getPreCommit() {
 454             assertNotNull("preCommit was not invoked", preCommit);
 455             return preCommit;
 456         }
 457
 458         public FutureCallback<UnsignedLong> getCommit() {
 459             assertNotNull("commit was not invoked", commit);
 460             return commit;
 461         }
 462
 463         @Override
 464         public TransactionIdentifier getIdentifier() {
 465             return delegate.getIdentifier();
 466         }
 467
 468         @Override
 469         DataTreeCandidateTip getCandidate() {
 470             return delegate.getCandidate();
 471         }
 472
 473         @Override
 474         DataTreeModification getDataTreeModification() {
 475             return delegate.getDataTreeModification();
 476         }
 477
 478         @Override
 479         public void canCommit(final FutureCallback<Void> callback) {
 480             canCommit = mockFutureCallback(callback);
 481             delegate.canCommit(canCommit);
 482         }
 483
 484         @Override
 485         public void preCommit(final FutureCallback<DataTreeCandidate> callback) {
 486             preCommit = mockFutureCallback(callback);
 487             delegate.preCommit(preCommit);
 488         }
 489
 490         @Override
 491         public void commit(final FutureCallback<UnsignedLong> callback) {
 492             commit = mockFutureCallback(callback);
 493             delegate.commit(commit);
 494         }
 495
 496         @SuppressWarnings("unchecked")
 497         private static <T> FutureCallback<T> mockFutureCallback(final FutureCallback<T> actual) {
 498             FutureCallback<T> mock = mock(FutureCallback.class);
 499             doAnswer(invocation -> {
 500                 actual.onFailure(invocation.getArgumentAt(0, Throwable.class));
 501                 return null;
 502             }).when(mock).onFailure(any(Throwable.class));
 503
 504             doAnswer(invocation -> {
 505                 actual.onSuccess((T) invocation.getArgumentAt(0, Throwable.class));
 506                 return null;
 507             }).when(mock).onSuccess((T) any(Object.class));
 508
 509             return mock;
 510         }
 511
 512         @Override
 513         public void abort(final FutureCallback<Void> callback) {
 514             delegate.abort(callback);
 515         }
 516
 517         @Override
 518         public boolean isFailed() {
 519             return delegate.isFailed();
 520         }
 521
 522         @Override
 523         public State getState() {
 524             return delegate.getState();
 525         }
 526     }
 527 }