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