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