Fix test failure in ShardTest
[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / test / java / org / opendaylight / controller / cluster / datastore / ShardTest.java
index c31acdad9361c2dd07053da257bbcf66eb11e3a5..87cfae80820935e7109dbc1a325c088a645408b8 100644 (file)
@@ -11,9 +11,9 @@ package org.opendaylight.controller.cluster.datastore;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.inOrder;
 import static org.mockito.Mockito.mock;
@@ -32,6 +32,7 @@ import akka.persistence.SaveSnapshotSuccess;
 import akka.testkit.TestActorRef;
 import akka.util.Timeout;
 import com.google.common.base.Function;
+import com.google.common.base.Stopwatch;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.Uninterruptibles;
@@ -46,6 +47,9 @@ import org.junit.Test;
 import org.mockito.InOrder;
 import org.opendaylight.controller.cluster.DataPersistenceProvider;
 import org.opendaylight.controller.cluster.DelegatingPersistentDataProvider;
+import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier;
+import org.opendaylight.controller.cluster.access.concepts.MemberName;
+import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
 import org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException;
 import org.opendaylight.controller.cluster.datastore.identifiers.ShardIdentifier;
 import org.opendaylight.controller.cluster.datastore.jmx.mbeans.shard.ShardStats;
@@ -89,6 +93,8 @@ import org.opendaylight.controller.cluster.raft.base.messages.ElectionTimeout;
 import org.opendaylight.controller.cluster.raft.base.messages.FollowerInitialSyncUpStatus;
 import org.opendaylight.controller.cluster.raft.client.messages.FindLeader;
 import org.opendaylight.controller.cluster.raft.client.messages.FindLeaderReply;
+import org.opendaylight.controller.cluster.raft.client.messages.GetOnDemandRaftState;
+import org.opendaylight.controller.cluster.raft.client.messages.OnDemandRaftState;
 import org.opendaylight.controller.cluster.raft.messages.RequestVote;
 import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
 import org.opendaylight.controller.cluster.raft.policy.DisableElectionsRaftPolicy;
@@ -123,7 +129,7 @@ public class ShardTest extends AbstractShardTest {
     public void testRegisterChangeListener() throws Exception {
         new ShardTestKit(getSystem()) {{
             final TestActorRef<Shard> shard = actorFactory.createTestActor(
-                    newShardProps() "testRegisterChangeListener");
+                    newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()), "testRegisterChangeListener");
 
             waitUntilLeader(shard);
 
@@ -175,7 +181,7 @@ public class ShardTest extends AbstractShardTest {
                     // it does do a persist)
                     return new Shard(newShardBuilder()) {
                         @Override
-                        public void onReceiveCommand(final Object message) throws Exception {
+                        public void handleCommand(final Object message) {
                             if(message instanceof ElectionTimeout && firstElectionTimeout) {
                                 // Got the first ElectionTimeout. We don't forward it to the
                                 // base Shard yet until we've sent the RegisterChangeListener
@@ -198,13 +204,15 @@ public class ShardTest extends AbstractShardTest {
 
                                 onFirstElectionTimeout.countDown();
                             } else {
-                                super.onReceiveCommand(message);
+                                super.handleCommand(message);
                             }
                         }
                     };
                 }
             };
 
+            setupInMemorySnapshotStore();
+
             final MockDataChangeListener listener = new MockDataChangeListener(1);
             final ActorRef dclActor = actorFactory.createActor(DataChangeListener.props(listener),
                     "testRegisterChangeListenerWhenNotLeaderInitially-DataChangeListener");
@@ -213,9 +221,7 @@ public class ShardTest extends AbstractShardTest {
                     Props.create(new DelegatingShardCreator(creator)).withDispatcher(Dispatchers.DefaultDispatcherId()),
                     "testRegisterChangeListenerWhenNotLeaderInitially");
 
-            // Write initial data into the in-memory store.
             final YangInstanceIdentifier path = TestModel.TEST_PATH;
-            writeToStore(shard, path, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
 
             // Wait until the shard receives the first ElectionTimeout message.
             assertEquals("Got first ElectionTimeout", true,
@@ -230,10 +236,10 @@ public class ShardTest extends AbstractShardTest {
             assertNotNull("getListenerRegistrationPath", reply.getListenerRegistrationPath());
 
             // Sanity check - verify the shard is not the leader yet.
-            shard.tell(new FindLeader(), getRef());
+            shard.tell(FindLeader.INSTANCE, getRef());
             final FindLeaderReply findLeadeReply =
                     expectMsgClass(duration("5 seconds"), FindLeaderReply.class);
-            assertNull("Expected the shard not to be the leader", findLeadeReply.getLeaderActor());
+            assertFalse("Expected the shard not to be the leader", findLeadeReply.getLeaderActor().isPresent());
 
             // Signal the onChangeListenerRegistered latch to tell the thread above to proceed
             // with the election process.
@@ -249,7 +255,7 @@ public class ShardTest extends AbstractShardTest {
     public void testRegisterDataTreeChangeListener() throws Exception {
         new ShardTestKit(getSystem()) {{
             final TestActorRef<Shard> shard = actorFactory.createTestActor(
-                    newShardProps(), "testRegisterDataTreeChangeListener");
+                    newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()), "testRegisterDataTreeChangeListener");
 
             waitUntilLeader(shard);
 
@@ -285,10 +291,9 @@ public class ShardTest extends AbstractShardTest {
 
                 @Override
                 public Shard create() throws Exception {
-                    return new Shard(Shard.builder().id(shardID).datastoreContext(
-                            dataStoreContextBuilder.persistent(false).build()).schemaContext(SCHEMA_CONTEXT)) {
+                    return new Shard(newShardBuilder()) {
                         @Override
-                        public void onReceiveCommand(final Object message) throws Exception {
+                        public void handleCommand(final Object message) {
                             if(message instanceof ElectionTimeout && firstElectionTimeout) {
                                 firstElectionTimeout = false;
                                 final ActorRef self = getSelf();
@@ -303,13 +308,15 @@ public class ShardTest extends AbstractShardTest {
 
                                 onFirstElectionTimeout.countDown();
                             } else {
-                                super.onReceiveCommand(message);
+                                super.handleCommand(message);
                             }
                         }
                     };
                 }
             };
 
+            setupInMemorySnapshotStore();
+
             final MockDataTreeChangeListener listener = new MockDataTreeChangeListener(1);
             final ActorRef dclActor = actorFactory.createActor(DataTreeChangeListenerActor.props(listener),
                     "testDataTreeChangeListenerNotifiedWhenNotTheLeaderOnRegistration-DataChangeListener");
@@ -319,7 +326,6 @@ public class ShardTest extends AbstractShardTest {
                     "testDataTreeChangeListenerNotifiedWhenNotTheLeaderOnRegistration");
 
             final YangInstanceIdentifier path = TestModel.TEST_PATH;
-            writeToStore(shard, path, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
 
             assertEquals("Got first ElectionTimeout", true,
                 onFirstElectionTimeout.await(5, TimeUnit.SECONDS));
@@ -329,12 +335,11 @@ public class ShardTest extends AbstractShardTest {
                 RegisterDataTreeChangeListenerReply.class);
             assertNotNull("getListenerRegistratioznPath", reply.getListenerRegistrationPath());
 
-            shard.tell(new FindLeader(), getRef());
+            shard.tell(FindLeader.INSTANCE, getRef());
             final FindLeaderReply findLeadeReply =
                     expectMsgClass(duration("5 seconds"), FindLeaderReply.class);
-            assertNull("Expected the shard not to be the leader", findLeadeReply.getLeaderActor());
+            assertFalse("Expected the shard not to be the leader", findLeadeReply.getLeaderActor().isPresent());
 
-            writeToStore(shard, path, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
 
             onChangeListenerRegistered.countDown();
 
@@ -352,7 +357,7 @@ public class ShardTest extends AbstractShardTest {
 
             shard.tell(new UpdateSchemaContext(TestModel.createTestContext()), getRef());
 
-            shard.tell(new CreateTransaction("txn-1", TransactionType.READ_ONLY.ordinal(), null,
+            shard.tell(new CreateTransaction(nextTransactionId(), TransactionType.READ_ONLY.ordinal(),
                     DataStoreVersions.CURRENT_VERSION).toSerializable(), getRef());
 
             final CreateTransactionReply reply = expectMsgClass(duration("3 seconds"),
@@ -360,7 +365,7 @@ public class ShardTest extends AbstractShardTest {
 
             final String path = reply.getTransactionPath().toString();
             assertTrue("Unexpected transaction path " + path,
-                    path.contains("akka://test/user/testCreateTransaction/shard-txn-1"));
+                    path.startsWith("akka://test/user/testCreateTransaction/shard-member-1:ShardTransactionTest@0:"));
         }};
     }
 
@@ -371,7 +376,7 @@ public class ShardTest extends AbstractShardTest {
 
             waitUntilLeader(shard);
 
-            shard.tell(new CreateTransaction("txn-1",TransactionType.READ_ONLY.ordinal(), "foobar",
+            shard.tell(new CreateTransaction(nextTransactionId(),TransactionType.READ_ONLY.ordinal(),
                     DataStoreVersions.CURRENT_VERSION).toSerializable(), getRef());
 
             final CreateTransactionReply reply = expectMsgClass(duration("3 seconds"),
@@ -379,52 +384,24 @@ public class ShardTest extends AbstractShardTest {
 
             final String path = reply.getTransactionPath().toString();
             assertTrue("Unexpected transaction path " + path,
-                    path.contains("akka://test/user/testCreateTransactionOnChain/shard-txn-1"));
+                    path.startsWith("akka://test/user/testCreateTransactionOnChain/shard-member-1:ShardTransactionTest@0:"));
         }};
     }
 
-    @SuppressWarnings("serial")
     @Test
     public void testPeerAddressResolved() throws Exception {
         new ShardTestKit(getSystem()) {{
-            final CountDownLatch recoveryComplete = new CountDownLatch(1);
-            class TestShard extends Shard {
-                TestShard() {
-                    super(Shard.builder().id(shardID).datastoreContext(newDatastoreContext()).
-                            peerAddresses(Collections.<String, String>singletonMap(shardID.toString(), null)).
-                            schemaContext(SCHEMA_CONTEXT));
-                }
-
-                String getPeerAddress(String id) {
-                    return getRaftActorContext().getPeerAddress(id);
-                }
-
-                @Override
-                protected void onRecoveryComplete() {
-                    try {
-                        super.onRecoveryComplete();
-                    } finally {
-                        recoveryComplete.countDown();
-                    }
-                }
-            }
-
-            final TestActorRef<Shard> shard = actorFactory.createTestActor(
-                    Props.create(new DelegatingShardCreator(new Creator<Shard>() {
-                        @Override
-                        public TestShard create() throws Exception {
-                            return new TestShard();
-                        }
-                    })), "testPeerAddressResolved");
-
-            assertEquals("Recovery complete", true,
-                Uninterruptibles.awaitUninterruptibly(recoveryComplete, 5, TimeUnit.SECONDS));
+            ShardIdentifier peerID = ShardIdentifier.create("inventory", MemberName.forName("member-2"), "config");
+            final TestActorRef<Shard> shard = actorFactory.createTestActor(newShardBuilder().
+                    peerAddresses(Collections.<String, String>singletonMap(peerID.toString(), null)).props().
+                        withDispatcher(Dispatchers.DefaultDispatcherId()), "testPeerAddressResolved");
 
             final String address = "akka://foobar";
-            shard.underlyingActor().onReceiveCommand(new PeerAddressResolved(shardID.toString(), address));
+            shard.tell(new PeerAddressResolved(peerID.toString(), address), ActorRef.noSender());
 
-            assertEquals("getPeerAddress", address,
-                ((TestShard) shard.underlyingActor()).getPeerAddress(shardID.toString()));
+            shard.tell(GetOnDemandRaftState.INSTANCE, getRef());
+            OnDemandRaftState state = expectMsgClass(OnDemandRaftState.class);
+            assertEquals("getPeerAddress", address, state.getPeerAddresses().get(peerID.toString()));
         }};
     }
 
@@ -445,7 +422,7 @@ public class ShardTest extends AbstractShardTest {
 
         writeToStore(store, TestModel.TEST_PATH, container);
 
-        final YangInstanceIdentifier root = YangInstanceIdentifier.builder().build();
+        final YangInstanceIdentifier root = YangInstanceIdentifier.EMPTY;
         final NormalizedNode<?,?> expected = readStore(store, root);
 
         final Snapshot snapshot = Snapshot.create(SerializationUtils.serializeNormalizedNode(expected),
@@ -460,7 +437,8 @@ public class ShardTest extends AbstractShardTest {
 
     @Test
     public void testApplyState() throws Exception {
-        final TestActorRef<Shard> shard = actorFactory.createTestActor(newShardProps(), "testApplyState");
+        final TestActorRef<Shard> shard = actorFactory.createTestActor(
+                newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()), "testApplyState");
 
         ShardTestKit.waitUntilLeader(shard);
 
@@ -470,13 +448,24 @@ public class ShardTest extends AbstractShardTest {
         writeMod.write(TestModel.TEST_PATH, node);
         writeMod.ready();
 
-        final ApplyState applyState = new ApplyState(null, "test", new ReplicatedLogImplEntry(1, 2,
-                payloadForModification(source, writeMod)));
+        final TransactionIdentifier tx = nextTransactionId();
+        final ApplyState applyState = new ApplyState(null, tx,
+            new ReplicatedLogImplEntry(1, 2, payloadForModification(source, writeMod, tx)));
+
+        shard.tell(applyState, shard);
+
+        Stopwatch sw = Stopwatch.createStarted();
+        while(sw.elapsed(TimeUnit.SECONDS) <= 5) {
+            Uninterruptibles.sleepUninterruptibly(75, TimeUnit.MILLISECONDS);
 
-        shard.underlyingActor().onReceiveCommand(applyState);
+            final NormalizedNode<?,?> actual = readStore(shard, TestModel.TEST_PATH);
+            if(actual != null) {
+                assertEquals("Applied state", node, actual);
+                return;
+            }
+        }
 
-        final NormalizedNode<?,?> actual = readStore(shard, TestModel.TEST_PATH);
-        assertEquals("Applied state", node, actual);
+        fail("State was not applied");
     }
 
     @Test
@@ -490,7 +479,8 @@ public class ShardTest extends AbstractShardTest {
         InMemoryJournal.addEntry(shardID.toString(), 0, DUMMY_DATA);
 
         // Set up the InMemoryJournal.
-        InMemoryJournal.addEntry(shardID.toString(), 1, new ReplicatedLogImplEntry(0, 1, payloadForModification(source, writeMod)));
+        InMemoryJournal.addEntry(shardID.toString(), 1, new ReplicatedLogImplEntry(0, 1,
+            payloadForModification(source, writeMod, nextTransactionId())));
 
         final int nListEntries = 16;
         final Set<Integer> listEntryKeys = new HashSet<>();
@@ -505,8 +495,9 @@ public class ShardTest extends AbstractShardTest {
             final DataTreeModification mod = source.takeSnapshot().newModification();
             mod.merge(path, ImmutableNodes.mapEntry(TestModel.OUTER_LIST_QNAME, TestModel.ID_QNAME, i));
             mod.ready();
+
             InMemoryJournal.addEntry(shardID.toString(), i+1, new ReplicatedLogImplEntry(i, 1,
-                payloadForModification(source, mod)));
+                payloadForModification(source, mod, nextTransactionId())));
         }
 
         InMemoryJournal.addEntry(shardID.toString(), nListEntries + 2,
@@ -528,19 +519,19 @@ public class ShardTest extends AbstractShardTest {
 
             final ShardDataTree dataStore = shard.underlyingActor().getDataStore();
 
-            final String transactionID1 = "tx1";
+            final TransactionIdentifier transactionID1 = nextTransactionId();
             final MutableCompositeModification modification1 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort1 = setupMockWriteTransaction("cohort1", dataStore,
                     TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME), modification1);
 
-            final String transactionID2 = "tx2";
+            final TransactionIdentifier transactionID2 = nextTransactionId();
             final MutableCompositeModification modification2 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort2 = setupMockWriteTransaction("cohort2", dataStore,
                     TestModel.OUTER_LIST_PATH,
                     ImmutableNodes.mapNodeBuilder(TestModel.OUTER_LIST_QNAME).build(),
                     modification2);
 
-            final String transactionID3 = "tx3";
+            final TransactionIdentifier transactionID3 = nextTransactionId();
             final MutableCompositeModification modification3 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort3 = setupMockWriteTransaction("cohort3", dataStore,
                     YangInstanceIdentifier.builder(TestModel.OUTER_LIST_PATH)
@@ -628,9 +619,9 @@ public class ShardTest extends AbstractShardTest {
             }
 
             class OnCanCommitFutureComplete extends OnFutureComplete {
-                private final String transactionID;
+                private final TransactionIdentifier transactionID;
 
-                OnCanCommitFutureComplete(final String transactionID) {
+                OnCanCommitFutureComplete(final TransactionIdentifier transactionID) {
                     super(CanCommitTransactionReply.class);
                     this.transactionID = transactionID;
                 }
@@ -689,19 +680,16 @@ public class ShardTest extends AbstractShardTest {
 
             waitUntilLeader(shard);
 
-            final String transactionID = "tx";
+            final TransactionIdentifier transactionID = nextTransactionId();
             final FiniteDuration duration = duration("5 seconds");
 
             final AtomicReference<ShardDataTreeCohort> mockCohort = new AtomicReference<>();
-            final ShardCommitCoordinator.CohortDecorator cohortDecorator = new ShardCommitCoordinator.CohortDecorator() {
-                @Override
-                public ShardDataTreeCohort decorate(final String txID, final ShardDataTreeCohort actual) {
-                    if(mockCohort.get() == null) {
-                        mockCohort.set(createDelegatingMockCohort("cohort", actual));
-                    }
-
-                    return mockCohort.get();
+            final ShardCommitCoordinator.CohortDecorator cohortDecorator = (txID, actual) -> {
+                if(mockCohort.get() == null) {
+                    mockCohort.set(createDelegatingMockCohort("cohort", actual));
                 }
+
+                return mockCohort.get();
             };
 
             shard.underlyingActor().getCommitCoordinator().setCohortDecorator(cohortDecorator);
@@ -755,19 +743,16 @@ public class ShardTest extends AbstractShardTest {
 
             waitUntilLeader(shard);
 
-            final String transactionID = "tx";
+            final TransactionIdentifier transactionID = nextTransactionId();
             final FiniteDuration duration = duration("5 seconds");
 
             final AtomicReference<ShardDataTreeCohort> mockCohort = new AtomicReference<>();
-            final ShardCommitCoordinator.CohortDecorator cohortDecorator = new ShardCommitCoordinator.CohortDecorator() {
-                @Override
-                public ShardDataTreeCohort decorate(final String txID, final ShardDataTreeCohort actual) {
-                    if(mockCohort.get() == null) {
-                        mockCohort.set(createDelegatingMockCohort("cohort", actual));
-                    }
-
-                    return mockCohort.get();
+            final ShardCommitCoordinator.CohortDecorator cohortDecorator = (txID, actual) -> {
+                if(mockCohort.get() == null) {
+                    mockCohort.set(createDelegatingMockCohort("cohort", actual));
                 }
+
+                return mockCohort.get();
             };
 
             shard.underlyingActor().getCommitCoordinator().setCohortDecorator(cohortDecorator);
@@ -810,8 +795,8 @@ public class ShardTest extends AbstractShardTest {
 
             waitUntilLeader(shard);
 
-            final String transactionID = "tx1";
-            final BatchedModifications batched = new BatchedModifications(transactionID, DataStoreVersions.CURRENT_VERSION, null);
+            final TransactionIdentifier transactionID = nextTransactionId();
+            final BatchedModifications batched = new BatchedModifications(transactionID, DataStoreVersions.CURRENT_VERSION);
             batched.setReady(true);
             batched.setTotalMessagesSent(2);
 
@@ -837,20 +822,20 @@ public class ShardTest extends AbstractShardTest {
             // Test merge with invalid data. An exception should occur when the merge is applied. Note that
             // write will not validate the children for performance reasons.
 
-            String transactionID = "tx1";
+            TransactionIdentifier transactionID = nextTransactionId();
 
             ContainerNode invalidData = ImmutableContainerNodeBuilder.create().withNodeIdentifier(
                     new YangInstanceIdentifier.NodeIdentifier(TestModel.TEST_QNAME)).
                         withChild(ImmutableNodes.leafNode(TestModel.JUNK_QNAME, "junk")).build();
 
-            BatchedModifications batched = new BatchedModifications(transactionID, CURRENT_VERSION, null);
+            BatchedModifications batched = new BatchedModifications(transactionID, CURRENT_VERSION);
             batched.addModification(new MergeModification(TestModel.TEST_PATH, invalidData));
             shard.tell(batched, getRef());
             Failure failure = expectMsgClass(duration("5 seconds"), akka.actor.Status.Failure.class);
 
             Throwable cause = failure.cause();
 
-            batched = new BatchedModifications(transactionID, DataStoreVersions.CURRENT_VERSION, null);
+            batched = new BatchedModifications(transactionID, DataStoreVersions.CURRENT_VERSION);
             batched.setReady(true);
             batched.setTotalMessagesSent(2);
 
@@ -870,9 +855,9 @@ public class ShardTest extends AbstractShardTest {
 
             waitUntilLeader(shard);
 
-            final String transactionChainID = "txChain";
-            final String transactionID1 = "tx1";
-            final String transactionID2 = "tx2";
+            final LocalHistoryIdentifier historyId = nextHistoryId();
+            final TransactionIdentifier transactionID1 = new TransactionIdentifier(historyId, 0);
+            final TransactionIdentifier transactionID2 = new TransactionIdentifier(historyId, 1);
 
             final FiniteDuration duration = duration("5 seconds");
 
@@ -880,14 +865,13 @@ public class ShardTest extends AbstractShardTest {
 
             final ContainerNode containerNode = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
             final YangInstanceIdentifier path = TestModel.TEST_PATH;
-            shard.tell(newBatchedModifications(transactionID1, transactionChainID, path,
-                    containerNode, true, false, 1), getRef());
+            shard.tell(newBatchedModifications(transactionID1, path, containerNode, true, false, 1), getRef());
             expectMsgClass(duration, ReadyTransactionReply.class);
 
             // Create a read Tx on the same chain.
 
             shard.tell(new CreateTransaction(transactionID2, TransactionType.READ_ONLY.ordinal(),
-                    transactionChainID, DataStoreVersions.CURRENT_VERSION).toSerializable(), getRef());
+                    DataStoreVersions.CURRENT_VERSION).toSerializable(), getRef());
 
             final CreateTransactionReply createReply = expectMsgClass(duration("3 seconds"), CreateTransactionReply.class);
 
@@ -938,13 +922,14 @@ public class ShardTest extends AbstractShardTest {
             };
 
             final TestActorRef<Shard> shard = actorFactory.createTestActor(
-                    Props.create(new DelegatingShardCreator(creator)), "testOnBatchedModificationsWhenNotLeader");
+                    Props.create(new DelegatingShardCreator(creator)).
+                        withDispatcher(Dispatchers.DefaultDispatcherId()), "testOnBatchedModificationsWhenNotLeader");
 
             waitUntilLeader(shard);
 
             overrideLeaderCalls.set(true);
 
-            final BatchedModifications batched = new BatchedModifications("tx", DataStoreVersions.CURRENT_VERSION, "");
+            final BatchedModifications batched = new BatchedModifications(nextTransactionId(), DataStoreVersions.CURRENT_VERSION);
 
             shard.tell(batched, ActorRef.noSender());
 
@@ -963,24 +948,29 @@ public class ShardTest extends AbstractShardTest {
 
             waitUntilNoLeader(shard);
 
-            shard.tell(new BatchedModifications("tx", DataStoreVersions.CURRENT_VERSION, ""), getRef());
+            final TransactionIdentifier txId = nextTransactionId();
+            shard.tell(new BatchedModifications(txId, DataStoreVersions.CURRENT_VERSION), getRef());
             Failure failure = expectMsgClass(Failure.class);
             assertEquals("Failure cause type", NoShardLeaderException.class, failure.cause().getClass());
 
-            shard.tell(prepareForwardedReadyTransaction(mock(ShardDataTreeCohort.class), "tx",
+            shard.tell(prepareForwardedReadyTransaction(mock(ShardDataTreeCohort.class), txId,
                     DataStoreVersions.CURRENT_VERSION, true), getRef());
             failure = expectMsgClass(Failure.class);
             assertEquals("Failure cause type", NoShardLeaderException.class, failure.cause().getClass());
 
-            shard.tell(new ReadyLocalTransaction("tx", mock(DataTreeModification.class), true), getRef());
+            shard.tell(new ReadyLocalTransaction(txId, mock(DataTreeModification.class), true), getRef());
             failure = expectMsgClass(Failure.class);
             assertEquals("Failure cause type", NoShardLeaderException.class, failure.cause().getClass());
         }};
     }
 
     @Test
-    public void testReadyWithImmediateCommit() throws Exception{
+    public void testReadyWithReadWriteImmediateCommit() throws Exception{
         testReadyWithImmediateCommit(true);
+    }
+
+    @Test
+    public void testReadyWithWriteOnlyImmediateCommit() throws Exception{
         testReadyWithImmediateCommit(false);
     }
 
@@ -994,7 +984,7 @@ public class ShardTest extends AbstractShardTest {
 
             final ShardDataTree dataStore = shard.underlyingActor().getDataStore();
 
-            final String transactionID = "tx1";
+            final TransactionIdentifier transactionID = nextTransactionId();
             final MutableCompositeModification modification = new MutableCompositeModification();
             final NormalizedNode<?, ?> containerNode = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
             final ShardDataTreeCohort cohort = setupMockWriteTransaction("cohort", dataStore,
@@ -1034,7 +1024,7 @@ public class ShardTest extends AbstractShardTest {
             final MapNode mergeData = ImmutableNodes.mapNodeBuilder(TestModel.OUTER_LIST_QNAME).build();
             new MergeModification(TestModel.OUTER_LIST_PATH, mergeData).apply(modification);
 
-            final String txId = "tx1";
+            final TransactionIdentifier txId = nextTransactionId();
             modification.ready();
             final ReadyLocalTransaction readyMessage = new ReadyLocalTransaction(txId, modification, true);
 
@@ -1065,8 +1055,8 @@ public class ShardTest extends AbstractShardTest {
             final MapNode mergeData = ImmutableNodes.mapNodeBuilder(TestModel.OUTER_LIST_QNAME).build();
             new MergeModification(TestModel.OUTER_LIST_PATH, mergeData).apply(modification);
 
-            final String txId = "tx1";
-                modification.ready();
+            final TransactionIdentifier txId = nextTransactionId();
+            modification.ready();
             final ReadyLocalTransaction readyMessage = new ReadyLocalTransaction(txId, modification, false);
 
             shard.tell(readyMessage, getRef());
@@ -1091,9 +1081,13 @@ public class ShardTest extends AbstractShardTest {
     }
 
     @Test
-    public void testCommitWithPersistenceDisabled() throws Throwable {
+    public void testReadWriteCommitWithPersistenceDisabled() throws Throwable {
+        testCommitWithPersistenceDisabled(true);
+    }
+
+    @Test
+    public void testWriteOnlyCommitWithPersistenceDisabled() throws Throwable {
         testCommitWithPersistenceDisabled(true);
-        testCommitWithPersistenceDisabled(false);
     }
 
     private void testCommitWithPersistenceDisabled(final boolean readWrite) throws Throwable {
@@ -1109,7 +1103,7 @@ public class ShardTest extends AbstractShardTest {
 
             // Setup a simulated transactions with a mock cohort.
 
-            final String transactionID = "tx";
+            final TransactionIdentifier transactionID = nextTransactionId();
             final MutableCompositeModification modification = new MutableCompositeModification();
             final NormalizedNode<?, ?> containerNode = ImmutableNodes.containerNode(TestModel.TEST_QNAME);
             final ShardDataTreeCohort cohort = setupMockWriteTransaction("cohort", dataStore,
@@ -1143,8 +1137,12 @@ public class ShardTest extends AbstractShardTest {
     }
 
     @Test
-    public void testCommitWhenTransactionHasNoModifications() {
+    public void testReadWriteCommitWhenTransactionHasNoModifications() {
         testCommitWhenTransactionHasNoModifications(true);
+    }
+
+    @Test
+    public void testWriteOnlyCommitWhenTransactionHasNoModifications() {
         testCommitWhenTransactionHasNoModifications(false);
     }
 
@@ -1159,7 +1157,7 @@ public class ShardTest extends AbstractShardTest {
 
                 waitUntilLeader(shard);
 
-                final String transactionID = "tx1";
+                final TransactionIdentifier transactionID = nextTransactionId();
                 final MutableCompositeModification modification = new MutableCompositeModification();
                 final ShardDataTreeCohort cohort = mock(ShardDataTreeCohort.class, "cohort1");
                 doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort).canCommit();
@@ -1201,8 +1199,12 @@ public class ShardTest extends AbstractShardTest {
     }
 
     @Test
-    public void testCommitWhenTransactionHasModifications() {
+    public void testReadWriteCommitWhenTransactionHasModifications() {
         testCommitWhenTransactionHasModifications(true);
+    }
+
+    @Test
+    public void testWriteOnlyCommitWhenTransactionHasModifications() {
         testCommitWhenTransactionHasModifications(false);
     }
 
@@ -1215,9 +1217,9 @@ public class ShardTest extends AbstractShardTest {
 
                 waitUntilLeader(shard);
 
-                final String transactionID = "tx1";
+                final TransactionIdentifier transactionID = nextTransactionId();
                 final MutableCompositeModification modification = new MutableCompositeModification();
-                modification.addModification(new DeleteModification(YangInstanceIdentifier.builder().build()));
+                modification.addModification(new DeleteModification(YangInstanceIdentifier.EMPTY));
                 final ShardDataTreeCohort cohort = mock(ShardDataTreeCohort.class, "cohort1");
                 doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort).canCommit();
                 doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort).preCommit();
@@ -1274,15 +1276,15 @@ public class ShardTest extends AbstractShardTest {
             // Setup 2 simulated transactions with mock cohorts. The first one fails in the
             // commit phase.
 
-            final String transactionID1 = "tx1";
+            final TransactionIdentifier transactionID1 = nextTransactionId();
             final MutableCompositeModification modification1 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort1 = mock(ShardDataTreeCohort.class, "cohort1");
             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort1).canCommit();
             doReturn(Futures.immediateFuture(null)).when(cohort1).preCommit();
-            doReturn(Futures.immediateFailedFuture(new IllegalStateException("mock"))).when(cohort1).commit();
+            doReturn(Futures.immediateFailedFuture(new RuntimeException("mock"))).when(cohort1).commit();
             doReturn(mockCandidate("cohort1-candidate")).when(cohort1).getCandidate();
 
-            final String transactionID2 = "tx2";
+            final TransactionIdentifier transactionID2 = nextTransactionId();
             final MutableCompositeModification modification2 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort2 = mock(ShardDataTreeCohort.class, "cohort2");
             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort2).canCommit();
@@ -1349,13 +1351,13 @@ public class ShardTest extends AbstractShardTest {
 
             waitUntilLeader(shard);
 
-            final String transactionID1 = "tx1";
+            final TransactionIdentifier transactionID1 = nextTransactionId();
             final MutableCompositeModification modification1 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort1 = mock(ShardDataTreeCohort.class, "cohort1");
             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort1).canCommit();
             doReturn(Futures.immediateFailedFuture(new IllegalStateException("mock"))).when(cohort1).preCommit();
 
-            final String transactionID2 = "tx2";
+            final TransactionIdentifier transactionID2 = nextTransactionId();
             final MutableCompositeModification modification2 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort2 = mock(ShardDataTreeCohort.class, "cohort2");
             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort2).canCommit();
@@ -1423,7 +1425,7 @@ public class ShardTest extends AbstractShardTest {
 
             final FiniteDuration duration = duration("5 seconds");
 
-            final String transactionID1 = "tx1";
+            final TransactionIdentifier transactionID1 = nextTransactionId();
             final MutableCompositeModification modification = new MutableCompositeModification();
             final ShardDataTreeCohort cohort = mock(ShardDataTreeCohort.class, "cohort1");
             doReturn(Futures.immediateFailedFuture(new IllegalStateException("mock"))).when(cohort).canCommit();
@@ -1440,7 +1442,7 @@ public class ShardTest extends AbstractShardTest {
 
             reset(cohort);
 
-            final String transactionID2 = "tx2";
+            final TransactionIdentifier transactionID2 = nextTransactionId();
             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort).canCommit();
 
             shard.tell(prepareReadyTransactionMessage(readWrite, shard.underlyingActor(), cohort, transactionID2, modification), getRef());
@@ -1469,7 +1471,7 @@ public class ShardTest extends AbstractShardTest {
 
             final FiniteDuration duration = duration("5 seconds");
 
-            final String transactionID1 = "tx1";
+            final TransactionIdentifier transactionID1 = nextTransactionId();
             final MutableCompositeModification modification = new MutableCompositeModification();
             final ShardDataTreeCohort cohort = mock(ShardDataTreeCohort.class, "cohort1");
             doReturn(Futures.immediateFuture(Boolean.FALSE)).when(cohort).canCommit();
@@ -1488,7 +1490,7 @@ public class ShardTest extends AbstractShardTest {
 
             reset(cohort);
 
-            final String transactionID2 = "tx2";
+            final TransactionIdentifier transactionID2 = nextTransactionId();
             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort).canCommit();
 
             shard.tell(prepareReadyTransactionMessage(readWrite, shard.underlyingActor(), cohort, transactionID2, modification), getRef());
@@ -1517,7 +1519,7 @@ public class ShardTest extends AbstractShardTest {
 
             final FiniteDuration duration = duration("5 seconds");
 
-            final String transactionID1 = "tx1";
+            final TransactionIdentifier transactionID1 = nextTransactionId();
             final MutableCompositeModification modification = new MutableCompositeModification();
             final ShardDataTreeCohort cohort = mock(ShardDataTreeCohort.class, "cohort1");
             doReturn(Futures.immediateFailedFuture(new IllegalStateException("mock"))).when(cohort).canCommit();
@@ -1530,7 +1532,7 @@ public class ShardTest extends AbstractShardTest {
 
             reset(cohort);
 
-            final String transactionID2 = "tx2";
+            final TransactionIdentifier transactionID2 = nextTransactionId();
             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort).canCommit();
             doReturn(Futures.immediateFuture(null)).when(cohort).preCommit();
             doReturn(Futures.immediateFuture(null)).when(cohort).commit();
@@ -1538,6 +1540,7 @@ public class ShardTest extends AbstractShardTest {
             final DataTreeCandidateNode candidateRoot = mock(DataTreeCandidateNode.class);
             doReturn(ModificationType.UNMODIFIED).when(candidateRoot).getModificationType();
             doReturn(candidateRoot).when(candidate).getRootNode();
+            doReturn(YangInstanceIdentifier.EMPTY).when(candidate).getRootPath();
             doReturn(candidate).when(cohort).getCandidate();
 
             shard.tell(prepareReadyTransactionMessage(readWrite, shard.underlyingActor(), cohort, transactionID2, modification, true), getRef());
@@ -1562,12 +1565,12 @@ public class ShardTest extends AbstractShardTest {
 
             final FiniteDuration duration = duration("5 seconds");
 
-            final String transactionID = "tx1";
+            final TransactionIdentifier transactionID1 = nextTransactionId();
             final MutableCompositeModification modification = new MutableCompositeModification();
             final ShardDataTreeCohort cohort = mock(ShardDataTreeCohort.class, "cohort1");
             doReturn(Futures.immediateFuture(Boolean.FALSE)).when(cohort).canCommit();
 
-            shard.tell(prepareReadyTransactionMessage(readWrite, shard.underlyingActor(), cohort, transactionID, modification, true), getRef());
+            shard.tell(prepareReadyTransactionMessage(readWrite, shard.underlyingActor(), cohort, transactionID1, modification, true), getRef());
 
             expectMsgClass(duration, akka.actor.Status.Failure.class);
 
@@ -1575,7 +1578,7 @@ public class ShardTest extends AbstractShardTest {
 
             reset(cohort);
 
-            final String transactionID2 = "tx2";
+            final TransactionIdentifier transactionID2 = nextTransactionId();
             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort).canCommit();
             doReturn(Futures.immediateFuture(null)).when(cohort).preCommit();
             doReturn(Futures.immediateFuture(null)).when(cohort).commit();
@@ -1583,6 +1586,7 @@ public class ShardTest extends AbstractShardTest {
             final DataTreeCandidateNode candidateRoot = mock(DataTreeCandidateNode.class);
             doReturn(ModificationType.UNMODIFIED).when(candidateRoot).getModificationType();
             doReturn(candidateRoot).when(candidate).getRootNode();
+            doReturn(YangInstanceIdentifier.EMPTY).when(candidate).getRootPath();
             doReturn(candidate).when(cohort).getCandidate();
 
             shard.tell(prepareReadyTransactionMessage(readWrite, shard.underlyingActor(), cohort, transactionID2, modification, true), getRef());
@@ -1608,25 +1612,22 @@ public class ShardTest extends AbstractShardTest {
             final FiniteDuration duration = duration("5 seconds");
             final ShardDataTree dataStore = shard.underlyingActor().getDataStore();
 
-            final String transactionID = "tx1";
+            final TransactionIdentifier transactionID = nextTransactionId();
             final Function<ShardDataTreeCohort, ListenableFuture<Void>> preCommit =
-                          new Function<ShardDataTreeCohort, ListenableFuture<Void>>() {
-                @Override
-                public ListenableFuture<Void> apply(final ShardDataTreeCohort cohort) {
-                    final ListenableFuture<Void> preCommitFuture = cohort.preCommit();
-
-                    // Simulate an AbortTransaction message occurring during replication, after
-                    // persisting and before finishing the commit to the in-memory store.
-                    // We have no followers so due to optimizations in the RaftActor, it does not
-                    // attempt replication and thus we can't send an AbortTransaction message b/c
-                    // it would be processed too late after CommitTransaction completes. So we'll
-                    // simulate an AbortTransaction message occurring during replication by calling
-                    // the shard directly.
-                    //
-                    shard.underlyingActor().doAbortTransaction(transactionID, null);
-
-                    return preCommitFuture;
-                }
+                          cohort -> {
+                final ListenableFuture<Void> preCommitFuture = cohort.preCommit();
+
+                // Simulate an AbortTransaction message occurring during replication, after
+                // persisting and before finishing the commit to the in-memory store.
+                // We have no followers so due to optimizations in the RaftActor, it does not
+                // attempt replication and thus we can't send an AbortTransaction message b/c
+                // it would be processed too late after CommitTransaction completes. So we'll
+                // simulate an AbortTransaction message occurring during replication by calling
+                // the shard directly.
+                //
+                shard.underlyingActor().doAbortTransaction(transactionID, null);
+
+                return preCommitFuture;
             };
 
             final MutableCompositeModification modification = new MutableCompositeModification();
@@ -1680,7 +1681,7 @@ public class ShardTest extends AbstractShardTest {
 
             // Create 1st Tx - will timeout
 
-            final String transactionID1 = "tx1";
+            final TransactionIdentifier transactionID1 = nextTransactionId();
             final MutableCompositeModification modification1 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort1 = setupMockWriteTransaction("cohort1", dataStore,
                     YangInstanceIdentifier.builder(TestModel.OUTER_LIST_PATH)
@@ -1690,7 +1691,7 @@ public class ShardTest extends AbstractShardTest {
 
             // Create 2nd Tx
 
-            final String transactionID2 = "tx3";
+            final TransactionIdentifier transactionID2 = nextTransactionId();
             final MutableCompositeModification modification2 = new MutableCompositeModification();
             final YangInstanceIdentifier listNodePath = YangInstanceIdentifier.builder(TestModel.OUTER_LIST_PATH)
                 .nodeWithKey(TestModel.OUTER_LIST_QNAME, TestModel.ID_QNAME, 2).build();
@@ -1747,19 +1748,19 @@ public class ShardTest extends AbstractShardTest {
 
             final ShardDataTree dataStore = shard.underlyingActor().getDataStore();
 
-            final String transactionID1 = "tx1";
+            final TransactionIdentifier transactionID1 = nextTransactionId();
             final MutableCompositeModification modification1 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort1 = setupMockWriteTransaction("cohort1", dataStore,
                     TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME), modification1);
 
-            final String transactionID2 = "tx2";
+            final TransactionIdentifier transactionID2 = nextTransactionId();
             final MutableCompositeModification modification2 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort2 = setupMockWriteTransaction("cohort2", dataStore,
                     TestModel.OUTER_LIST_PATH,
                     ImmutableNodes.mapNodeBuilder(TestModel.OUTER_LIST_QNAME).build(),
                     modification2);
 
-            final String transactionID3 = "tx3";
+            final TransactionIdentifier transactionID3 = nextTransactionId();
             final MutableCompositeModification modification3 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort3 = setupMockWriteTransaction("cohort3", dataStore,
                     TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME), modification3);
@@ -1808,7 +1809,7 @@ public class ShardTest extends AbstractShardTest {
 
             final ShardDataTree dataStore = shard.underlyingActor().getDataStore();
 
-            final String transactionID1 = "tx1";
+            final TransactionIdentifier transactionID1 = nextTransactionId();
             final MutableCompositeModification modification1 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort1 = setupMockWriteTransaction("cohort1", dataStore,
                     TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME), modification1);
@@ -1816,7 +1817,7 @@ public class ShardTest extends AbstractShardTest {
             shard.tell(prepareReadyTransactionMessage(false, shard.underlyingActor(), cohort1, transactionID1, modification1), getRef());
             expectMsgClass(duration, ReadyTransactionReply.class);
 
-            final String transactionID2 = "tx2";
+            final TransactionIdentifier transactionID2 = nextTransactionId();
             final MutableCompositeModification modification2 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort2 = setupMockWriteTransaction("cohort2", dataStore,
                     TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME), modification2);
@@ -1824,7 +1825,7 @@ public class ShardTest extends AbstractShardTest {
             shard.tell(prepareReadyTransactionMessage(false, shard.underlyingActor(), cohort2, transactionID2, modification2), getRef());
             expectMsgClass(duration, ReadyTransactionReply.class);
 
-            final String transactionID3 = "tx3";
+            final TransactionIdentifier transactionID3 = nextTransactionId();
             final MutableCompositeModification modification3 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort3 = setupMockWriteTransaction("cohort3", dataStore,
                     TestModel.TEST2_PATH, ImmutableNodes.containerNode(TestModel.TEST2_QNAME), modification3);
@@ -1855,7 +1856,7 @@ public class ShardTest extends AbstractShardTest {
 
             final ShardDataTree dataStore = shard.underlyingActor().getDataStore();
 
-            final String transactionID1 = "tx1";
+            final TransactionIdentifier transactionID1 = nextTransactionId();
             final MutableCompositeModification modification1 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort1 = setupMockWriteTransaction("cohort1", dataStore,
                     TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME), modification1);
@@ -1870,7 +1871,7 @@ public class ShardTest extends AbstractShardTest {
 
             // Ready the second Tx.
 
-            final String transactionID2 = "tx2";
+            final TransactionIdentifier transactionID2 = nextTransactionId();
             final MutableCompositeModification modification2 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort2 = setupMockWriteTransaction("cohort2", dataStore,
                     TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME), modification2);
@@ -1880,7 +1881,7 @@ public class ShardTest extends AbstractShardTest {
 
             // Ready the third Tx.
 
-            final String transactionID3 = "tx3";
+            final TransactionIdentifier transactionID3 = nextTransactionId();
             final DataTreeModification modification3 = dataStore.newModification();
             new WriteModification(TestModel.TEST2_PATH, ImmutableNodes.containerNode(TestModel.TEST2_QNAME))
                     .apply(modification3);
@@ -1911,7 +1912,7 @@ public class ShardTest extends AbstractShardTest {
                     newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()),
                     "testCanCommitBeforeReadyFailure");
 
-            shard.tell(new CanCommitTransaction("tx", CURRENT_VERSION).toSerializable(), getRef());
+            shard.tell(new CanCommitTransaction(nextTransactionId(), CURRENT_VERSION).toSerializable(), getRef());
             expectMsgClass(duration("5 seconds"), akka.actor.Status.Failure.class);
         }};
     }
@@ -1932,13 +1933,13 @@ public class ShardTest extends AbstractShardTest {
 
             // Setup 2 simulated transactions with mock cohorts. The first one will be aborted.
 
-            final String transactionID1 = "tx1";
+            final TransactionIdentifier transactionID1 = nextTransactionId();
             final MutableCompositeModification modification1 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort1 = mock(ShardDataTreeCohort.class, "cohort1");
             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort1).canCommit();
             doReturn(Futures.immediateFuture(null)).when(cohort1).abort();
 
-            final String transactionID2 = "tx2";
+            final TransactionIdentifier transactionID2 = nextTransactionId();
             final MutableCompositeModification modification2 = new MutableCompositeModification();
             final ShardDataTreeCohort cohort2 = mock(ShardDataTreeCohort.class, "cohort2");
             doReturn(Futures.immediateFuture(Boolean.TRUE)).when(cohort2).canCommit();
@@ -1992,20 +1993,15 @@ public class ShardTest extends AbstractShardTest {
         new ShardTestKit(getSystem()) {{
             final AtomicReference<CountDownLatch> cleaupCheckLatch = new AtomicReference<>();
             @SuppressWarnings("serial")
-            final Creator<Shard> creator = new Creator<Shard>() {
+            final Creator<Shard> creator = () -> new Shard(newShardBuilder()) {
                 @Override
-                public Shard create() throws Exception {
-                    return new Shard(newShardBuilder()) {
-                        @Override
-                        public void onReceiveCommand(final Object message) throws Exception {
-                            super.onReceiveCommand(message);
-                            if(message.equals(TX_COMMIT_TIMEOUT_CHECK_MESSAGE)) {
-                                if(cleaupCheckLatch.get() != null) {
-                                    cleaupCheckLatch.get().countDown();
-                                }
-                            }
+                public void handleCommand(final Object message) {
+                    super.handleCommand(message);
+                    if(TX_COMMIT_TIMEOUT_CHECK_MESSAGE.equals(message)) {
+                        if(cleaupCheckLatch.get() != null) {
+                            cleaupCheckLatch.get().countDown();
                         }
-                    };
+                    }
                 }
             };
 
@@ -2015,8 +2011,7 @@ public class ShardTest extends AbstractShardTest {
 
             waitUntilLeader(shard);
 
-            final String transactionID = "tx1";
-
+            final TransactionIdentifier transactionID = nextTransactionId();
             final MutableCompositeModification modification = new MutableCompositeModification();
             final ShardDataTreeCohort cohort = mock(ShardDataTreeCohort.class, "cohort");
             doReturn(Futures.immediateFuture(null)).when(cohort).abort();
@@ -2064,7 +2059,6 @@ public class ShardTest extends AbstractShardTest {
         testCreateSnapshot(false, "testCreateSnapshotWithNonPersistentData");
     }
 
-    @SuppressWarnings("serial")
     private void testCreateSnapshot(final boolean persistent, final String shardActorName) throws Exception{
 
         final AtomicReference<CountDownLatch> latch = new AtomicReference<>(new CountDownLatch(1));
@@ -2096,7 +2090,8 @@ public class ShardTest extends AbstractShardTest {
                 public void handleCommand(final Object message) {
                     super.handleCommand(message);
 
-                    if (message instanceof SaveSnapshotSuccess || message.equals("commit_snapshot")) {
+                    // XXX:  commit_snapshot equality check references RaftActorSnapshotMessageSupport.COMMIT_SNAPSHOT
+                    if (message instanceof SaveSnapshotSuccess || "commit_snapshot".equals(message.toString())) {
                         latch.get().countDown();
                     }
                 }
@@ -2107,20 +2102,16 @@ public class ShardTest extends AbstractShardTest {
                 }
             }
 
-            final Creator<Shard> creator = new Creator<Shard>() {
-                @Override
-                public Shard create() throws Exception {
-                    return new TestShard(newShardBuilder());
-                }
-            };
+            final Creator<Shard> creator = () -> new TestShard(newShardBuilder());
 
             final TestActorRef<Shard> shard = actorFactory.createTestActor(
-                    Props.create(new DelegatingShardCreator(creator)), shardActorName);
+                    Props.create(new DelegatingShardCreator(creator)).
+                        withDispatcher(Dispatchers.DefaultDispatcherId()), shardActorName);
 
             waitUntilLeader(shard);
             writeToStore(shard, TestModel.TEST_PATH, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
 
-            final NormalizedNode<?,?> expectedRoot = readStore(shard, YangInstanceIdentifier.builder().build());
+            final NormalizedNode<?,?> expectedRoot = readStore(shard, YangInstanceIdentifier.EMPTY);
 
             // Trigger creation of a snapshot by ensuring
             final RaftActorContext raftActorContext = ((TestShard) shard.underlyingActor()).getRaftActorContext();
@@ -2167,16 +2158,16 @@ public class ShardTest extends AbstractShardTest {
         commitTransaction(store, putTransaction);
 
 
-        final NormalizedNode<?, ?> expected = readStore(store, YangInstanceIdentifier.builder().build());
+        final NormalizedNode<?, ?> expected = readStore(store, YangInstanceIdentifier.EMPTY);
 
         final DataTreeModification writeTransaction = store.takeSnapshot().newModification();
 
-        writeTransaction.delete(YangInstanceIdentifier.builder().build());
-        writeTransaction.write(YangInstanceIdentifier.builder().build(), expected);
+        writeTransaction.delete(YangInstanceIdentifier.EMPTY);
+        writeTransaction.write(YangInstanceIdentifier.EMPTY, expected);
 
         commitTransaction(store, writeTransaction);
 
-        final NormalizedNode<?, ?> actual = readStore(store, YangInstanceIdentifier.builder().build());
+        final NormalizedNode<?, ?> actual = readStore(store, YangInstanceIdentifier.EMPTY);
 
         assertEquals(expected, actual);
     }
@@ -2275,11 +2266,11 @@ public class ShardTest extends AbstractShardTest {
                 newShardProps().withDispatcher(Dispatchers.DefaultDispatcherId()),
                 "testFollowerInitialSyncStatus");
 
-        shard.underlyingActor().onReceiveCommand(new FollowerInitialSyncUpStatus(false, "member-1-shard-inventory-operational"));
+        shard.underlyingActor().handleNonRaftCommand(new FollowerInitialSyncUpStatus(false, "member-1-shard-inventory-operational"));
 
         assertEquals(false, shard.underlyingActor().getShardMBean().getFollowerInitialSyncStatus());
 
-        shard.underlyingActor().onReceiveCommand(new FollowerInitialSyncUpStatus(true, "member-1-shard-inventory-operational"));
+        shard.underlyingActor().handleNonRaftCommand(new FollowerInitialSyncUpStatus(true, "member-1-shard-inventory-operational"));
 
         assertEquals(true, shard.underlyingActor().getShardMBean().getFollowerInitialSyncStatus());
     }
@@ -2288,12 +2279,15 @@ public class ShardTest extends AbstractShardTest {
     public void testClusteredDataChangeListenerDelayedRegistration() throws Exception {
         new ShardTestKit(getSystem()) {{
             String testName = "testClusteredDataChangeListenerDelayedRegistration";
-            dataStoreContextBuilder.shardElectionTimeoutFactor(1000);
+            dataStoreContextBuilder.shardElectionTimeoutFactor(1000).
+                    customRaftPolicyImplementation(DisableElectionsRaftPolicy.class.getName());
 
             final MockDataChangeListener listener = new MockDataChangeListener(1);
             final ActorRef dclActor = actorFactory.createActor(DataChangeListener.props(listener),
                     actorFactory.generateActorId(testName + "-DataChangeListener"));
 
+            setupInMemorySnapshotStore();
+
             final TestActorRef<Shard> shard = actorFactory.createTestActor(
                     newShardBuilder().props().withDispatcher(Dispatchers.DefaultDispatcherId()),
                     actorFactory.generateActorId(testName + "-shard"));
@@ -2307,9 +2301,8 @@ public class ShardTest extends AbstractShardTest {
                 RegisterChangeListenerReply.class);
             assertNotNull("getListenerRegistrationPath", reply.getListenerRegistrationPath());
 
-            writeToStore(shard, path, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
-
-            shard.tell(new ElectionTimeout(), ActorRef.noSender());
+            shard.tell(DatastoreContext.newBuilderFrom(dataStoreContextBuilder.build()).
+                    customRaftPolicyImplementation(null).build(), ActorRef.noSender());
 
             listener.waitForChangeEvents();
         }};
@@ -2319,11 +2312,11 @@ public class ShardTest extends AbstractShardTest {
     public void testClusteredDataChangeListenerRegistration() throws Exception {
         new ShardTestKit(getSystem()) {{
             String testName = "testClusteredDataChangeListenerRegistration";
-            final ShardIdentifier followerShardID = ShardIdentifier.builder().memberName(
-                    actorFactory.generateActorId(testName + "-follower")).shardName("inventory").type("config").build();
+            final ShardIdentifier followerShardID = ShardIdentifier.create("inventory",
+                    MemberName.forName(actorFactory.generateActorId(testName + "-follower")), "config");
 
-            final ShardIdentifier leaderShardID = ShardIdentifier.builder().memberName(
-                    actorFactory.generateActorId(testName + "-leader")).shardName("inventory").type("config").build();
+            final ShardIdentifier leaderShardID = ShardIdentifier.create("inventory",
+                    MemberName.forName(actorFactory.generateActorId(testName + "-leader")), "config");
 
             final TestActorRef<Shard> followerShard = actorFactory.createTestActor(
                     Shard.builder().id(followerShardID).
@@ -2338,7 +2331,7 @@ public class ShardTest extends AbstractShardTest {
                             "akka://test/user/" + followerShardID.toString())).schemaContext(SCHEMA_CONTEXT).props().
                     withDispatcher(Dispatchers.DefaultDispatcherId()), leaderShardID.toString());
 
-            leaderShard.tell(new ElectionTimeout(), ActorRef.noSender());
+            leaderShard.tell(ElectionTimeout.INSTANCE, ActorRef.noSender());
             String leaderPath = waitUntilLeader(followerShard);
             assertEquals("Shard leader path", leaderShard.path().toString(), leaderPath);
 
@@ -2362,12 +2355,15 @@ public class ShardTest extends AbstractShardTest {
     public void testClusteredDataTreeChangeListenerDelayedRegistration() throws Exception {
         new ShardTestKit(getSystem()) {{
             String testName = "testClusteredDataTreeChangeListenerDelayedRegistration";
-            dataStoreContextBuilder.shardElectionTimeoutFactor(1000);
+            dataStoreContextBuilder.shardElectionTimeoutFactor(1000).
+                    customRaftPolicyImplementation(DisableElectionsRaftPolicy.class.getName());
 
             final MockDataTreeChangeListener listener = new MockDataTreeChangeListener(1);
             final ActorRef dclActor = actorFactory.createActor(DataTreeChangeListenerActor.props(listener),
                     actorFactory.generateActorId(testName + "-DataTreeChangeListener"));
 
+            setupInMemorySnapshotStore();
+
             final TestActorRef<Shard> shard = actorFactory.createTestActor(
                     newShardBuilder().props().withDispatcher(Dispatchers.DefaultDispatcherId()),
                     actorFactory.generateActorId(testName + "-shard"));
@@ -2381,9 +2377,8 @@ public class ShardTest extends AbstractShardTest {
                     RegisterDataTreeChangeListenerReply.class);
             assertNotNull("getListenerRegistrationPath", reply.getListenerRegistrationPath());
 
-            writeToStore(shard, path, ImmutableNodes.containerNode(TestModel.TEST_QNAME));
-
-            shard.tell(new ElectionTimeout(), ActorRef.noSender());
+            shard.tell(DatastoreContext.newBuilderFrom(dataStoreContextBuilder.build()).
+                    customRaftPolicyImplementation(null).build(), ActorRef.noSender());
 
             listener.waitForChangeEvents();
         }};
@@ -2393,11 +2388,11 @@ public class ShardTest extends AbstractShardTest {
     public void testClusteredDataTreeChangeListenerRegistration() throws Exception {
         new ShardTestKit(getSystem()) {{
             String testName = "testClusteredDataTreeChangeListenerRegistration";
-            final ShardIdentifier followerShardID = ShardIdentifier.builder().memberName(
-                    actorFactory.generateActorId(testName + "-follower")).shardName("inventory").type("config").build();
+            final ShardIdentifier followerShardID = ShardIdentifier.create("inventory",
+                    MemberName.forName(actorFactory.generateActorId(testName + "-follower")), "config");
 
-            final ShardIdentifier leaderShardID = ShardIdentifier.builder().memberName(
-                    actorFactory.generateActorId(testName + "-leader")).shardName("inventory").type("config").build();
+            final ShardIdentifier leaderShardID = ShardIdentifier.create("inventory",
+                    MemberName.forName(actorFactory.generateActorId(testName + "-leader")), "config");
 
             final TestActorRef<Shard> followerShard = actorFactory.createTestActor(
                     Shard.builder().id(followerShardID).
@@ -2412,7 +2407,7 @@ public class ShardTest extends AbstractShardTest {
                             "akka://test/user/" + followerShardID.toString())).schemaContext(SCHEMA_CONTEXT).props().
                     withDispatcher(Dispatchers.DefaultDispatcherId()), leaderShardID.toString());
 
-            leaderShard.tell(new ElectionTimeout(), ActorRef.noSender());
+            leaderShard.tell(ElectionTimeout.INSTANCE, ActorRef.noSender());
             String leaderPath = waitUntilLeader(followerShard);
             assertEquals("Shard leader path", leaderShard.path().toString(), leaderPath);