You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@sentry.apache.org by sp...@apache.org on 2018/05/31 03:32:26 UTC

[48/86] sentry git commit: SENTRY-2208: Refactor out Sentry service into own module from sentry-provider-db (Anthony Young-Garner, reviewed by Sergio Pena, Steve Moist, Na Li)

http://git-wip-us.apache.org/repos/asf/sentry/blob/7db84b2f/sentry-service/sentry-service-server/src/test/java/org/apache/sentry/provider/db/service/persistent/TestHMSFollower.java
----------------------------------------------------------------------
diff --git a/sentry-service/sentry-service-server/src/test/java/org/apache/sentry/provider/db/service/persistent/TestHMSFollower.java b/sentry-service/sentry-service-server/src/test/java/org/apache/sentry/provider/db/service/persistent/TestHMSFollower.java
new file mode 100644
index 0000000..0c66dd2
--- /dev/null
+++ b/sentry-service/sentry-service-server/src/test/java/org/apache/sentry/provider/db/service/persistent/TestHMSFollower.java
@@ -0,0 +1,1296 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package  org.apache.sentry.provider.db.service.persistent;
+
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.google.common.collect.Sets;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import junit.framework.Assert;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hive.conf.HiveConf;
+import org.apache.hadoop.hive.metastore.HiveMetaStoreClient;
+import org.apache.hadoop.hive.metastore.IMetaStoreClient.NotificationFilter;
+import org.apache.hadoop.hive.metastore.api.CurrentNotificationEventId;
+import org.apache.hadoop.hive.metastore.api.Database;
+import org.apache.hadoop.hive.metastore.api.FieldSchema;
+import org.apache.hadoop.hive.metastore.api.NotificationEvent;
+import org.apache.hadoop.hive.metastore.api.NotificationEventResponse;
+import org.apache.hadoop.hive.metastore.api.Partition;
+import org.apache.hadoop.hive.metastore.api.StorageDescriptor;
+import org.apache.hadoop.hive.metastore.api.Table;
+import org.apache.hadoop.hive.metastore.messaging.EventMessage;
+import org.apache.hadoop.hive.metastore.messaging.EventMessage.EventType;
+import org.apache.sentry.binding.hive.conf.HiveAuthzConf;
+import org.apache.sentry.binding.hive.conf.HiveAuthzConf.AuthzConfVars;
+import org.apache.sentry.binding.metastore.messaging.json.SentryJSONMessageFactory;
+import org.apache.sentry.core.common.utils.PubSub;
+import org.apache.sentry.hdfs.UniquePathsUpdate;
+import org.apache.sentry.service.thrift.SentryHMSClient;
+import org.apache.sentry.service.thrift.HiveConnectionFactory;
+import org.apache.sentry.service.thrift.HiveSimpleConnectionFactory;
+import org.apache.sentry.service.common.ServiceConstants;
+import org.apache.sentry.service.thrift.HMSClient;
+import org.apache.sentry.api.service.thrift.TSentryAuthorizable;
+import static org.apache.sentry.hdfs.ServiceConstants.ServerConfig.SENTRY_SERVICE_FULL_UPDATE_PUBSUB;
+
+import org.junit.Before;
+import org.junit.After;
+import org.junit.BeforeClass;
+import org.junit.Ignore;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import javax.security.auth.login.LoginException;
+
+public class TestHMSFollower {
+
+  private final static String hiveInstance = "server2";
+  private final static Configuration configuration = new Configuration();
+  private final SentryJSONMessageFactory messageFactory = new SentryJSONMessageFactory();
+  private final SentryStore sentryStore = Mockito.mock(SentryStore.class);
+  private static HiveSimpleConnectionFactory hiveConnectionFactory;
+
+  private final static HiveConnectionFactory hmsConnectionMock
+      = Mockito.mock(HiveConnectionFactory.class);
+  private final static HiveMetaStoreClient hmsClientMock
+      = Mockito.mock(HiveMetaStoreClient.class);
+
+  @BeforeClass
+  public static void setup() throws IOException, LoginException {
+    hiveConnectionFactory = new HiveSimpleConnectionFactory(configuration, new HiveConf());
+    hiveConnectionFactory.init();
+    configuration.set("sentry.hive.sync.create", "true");
+    configuration.set(SENTRY_SERVICE_FULL_UPDATE_PUBSUB, "true");
+
+    enableHdfsSyncInSentry(configuration);
+  }
+
+  @Before
+  public void setupMocks() throws Exception {
+    reset(hmsConnectionMock, hmsClientMock, sentryStore);
+    when(hmsConnectionMock.connect()).thenReturn(new HMSClient(hmsClientMock));
+  }
+
+  @After
+  public void resetConfig() throws Exception {
+    enableHdfsSyncInSentry(configuration);
+  }
+
+  private static void enableHdfsSyncInSentry(Configuration conf) {
+    // enable HDFS sync, so perm and path changes will be saved into DB
+    conf.set(ServiceConstants.ServerConfig.PROCESSOR_FACTORIES,
+            "org.apache.sentry.hdfs.SentryHDFSServiceProcessorFactory");
+    conf.set(ServiceConstants.ServerConfig.SENTRY_POLICY_STORE_PLUGINS,
+            "org.apache.sentry.hdfs.SentryPlugin");
+  }
+
+  private static void disableHdfsSyncInSentry(Configuration conf) {
+    // enable HDFS sync, so perm and path changes will be saved into DB
+    conf.set(ServiceConstants.ServerConfig.PROCESSOR_FACTORIES, "");
+    conf.set(ServiceConstants.ServerConfig.SENTRY_POLICY_STORE_PLUGINS, "");
+  }
+
+  @Test
+  public void testPersistAFullSnapshotWhenNoSnapshotAreProcessedYet() throws Exception {
+    /*
+     * TEST CASE
+     *
+     * Simulates (by using mocks) that Sentry has not processed any notifications, so this
+     * should trigger a new full HMS snapshot request with the eventId = 1
+     */
+
+    final long SENTRY_PROCESSED_EVENT_ID = SentryStore.EMPTY_NOTIFICATION_ID;
+    final long HMS_PROCESSED_EVENT_ID = 1L;
+
+    // Mock that returns a full snapshot
+    Map<String, Collection<String>> snapshotObjects = new HashMap<>();
+    snapshotObjects.put("db", Sets.newHashSet("/db"));
+    snapshotObjects.put("db.table", Sets.newHashSet("/db/table"));
+    PathsImage fullSnapshot = new PathsImage(snapshotObjects, HMS_PROCESSED_EVENT_ID, 1);
+
+    // Mock that returns the current HMS notification ID
+    when(hmsClientMock.getCurrentNotificationEventId())
+        .thenReturn(new CurrentNotificationEventId(fullSnapshot.getId()));
+
+    SentryHMSClient sentryHmsClient = Mockito.mock(SentryHMSClient.class);
+    when(sentryHmsClient.getFullSnapshot()).thenReturn(fullSnapshot);
+
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hmsConnectionMock, hiveInstance);
+    hmsFollower.setSentryHmsClient(sentryHmsClient);
+
+    // 1st run should get a full snapshot because AuthzPathsMapping is empty
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(SENTRY_PROCESSED_EVENT_ID);
+    when(sentryStore.isAuthzPathsMappingEmpty()).thenReturn(true);
+    when(sentryStore.isHmsNotificationEmpty()).thenReturn(true);
+    hmsFollower.run();
+    verify(sentryStore, times(1)).persistFullPathsImage(
+        fullSnapshot.getPathImage(), fullSnapshot.getId());
+    // Saving notificationID is in the same transaction of saving full snapshot
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(fullSnapshot.getId());
+
+    reset(sentryStore);
+
+    // 2nd run should not get a snapshot because is already processed
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(fullSnapshot.getId());
+    when(sentryStore.isAuthzPathsMappingEmpty()).thenReturn(false);
+    hmsFollower.run();
+    verify(sentryStore, times(0)).persistFullPathsImage(Mockito.anyMap(), Mockito.anyLong());
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(Mockito.anyLong());
+  }
+
+  @Test
+  public void testPersistAFullSnapshotWhenFullSnapshotTrigger() throws Exception {
+    /*
+     * TEST CASE
+     *
+     * Simulates (by using mocks) the following:
+     *
+     * HMS client always returns the paths image with the eventId == 1.
+     *
+     * On the 1st run:  Sentry has not processed any notifications, so this
+     * should trigger a new full HMS snapshot request with the eventId = 1
+     *
+     * On the 2nd run: Sentry store returns the latest eventId == 1,
+     * which matches the eventId returned by HMS client. Because of the match,
+     * no full update is triggered.
+     *
+     * On the 3d run: before the run, full update flag in HMSFollower is set via
+     * publish-subscribe mechanism.
+     * Sentry store still returns the latest eventId == 1,
+     * which matches the eventId returned by HMS client. Because of the match,
+     * no full update should be triggered. However, because of the trigger set,
+     * a new full HMS snapshot will be triggered.
+     *
+     * On the 4th run: Sentry store returns the latest eventId == 1,
+     * which matches the eventId returned by HMS client. Because of the match,
+     * no full update is triggered. This is to check that forced trigger set
+     * for run 3 only works once.
+     *
+     */
+
+    final long SENTRY_PROCESSED_EVENT_ID = SentryStore.EMPTY_NOTIFICATION_ID;
+    final long HMS_PROCESSED_EVENT_ID = 1L;
+
+    // Mock that returns a full snapshot
+    Map<String, Collection<String>> snapshotObjects = new HashMap<>();
+    snapshotObjects.put("db", Sets.newHashSet("/db"));
+    snapshotObjects.put("db.table", Sets.newHashSet("/db/table"));
+    PathsImage fullSnapshot = new PathsImage(snapshotObjects, HMS_PROCESSED_EVENT_ID, 1);
+
+    // Mock that returns the current HMS notification ID
+    when(hmsClientMock.getCurrentNotificationEventId())
+        .thenReturn(new CurrentNotificationEventId(fullSnapshot.getId()));
+
+    SentryHMSClient sentryHmsClient = Mockito.mock(SentryHMSClient.class);
+    when(sentryHmsClient.getFullSnapshot()).thenReturn(fullSnapshot);
+
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hmsConnectionMock, hiveInstance);
+    hmsFollower.setSentryHmsClient(sentryHmsClient);
+
+    // 1st run should get a full snapshot because AuthzPathsMapping is empty
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(SENTRY_PROCESSED_EVENT_ID);
+    when(sentryStore.isAuthzPathsMappingEmpty()).thenReturn(true);
+    when(sentryStore.isHmsNotificationEmpty()).thenReturn(true);
+    hmsFollower.run();
+    verify(sentryStore, times(1)).persistFullPathsImage(
+        fullSnapshot.getPathImage(), fullSnapshot.getId());
+    // Saving notificationID is in the same transaction of saving full snapshot
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(fullSnapshot.getId());
+
+    reset(sentryStore);
+
+    // 2nd run should not get a snapshot because is already processed
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(fullSnapshot.getId());
+    when(sentryStore.isAuthzPathsMappingEmpty()).thenReturn(false);
+    hmsFollower.run();
+    verify(sentryStore, times(0)).persistFullPathsImage(Mockito.anyMap(), Mockito.anyLong());
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(Mockito.anyLong());
+
+    reset(sentryStore);
+
+    // 3d run should not get a snapshot because is already processed,
+    // but because of full update trigger it will, as in the first run
+    PubSub.getInstance().publish(PubSub.Topic.HDFS_SYNC_HMS, "message");
+
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(fullSnapshot.getId());
+    when(sentryStore.isAuthzPathsMappingEmpty()).thenReturn(false);
+    hmsFollower.run();
+    verify(sentryStore, times(1)).persistFullPathsImage(
+        fullSnapshot.getPathImage(), fullSnapshot.getId());
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(fullSnapshot.getId());
+
+    reset(sentryStore);
+
+    // 4th run should not get a snapshot because is already processed and publish-subscribe
+    // trigger is only supposed to work once. This is exactly as 2nd run.
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(fullSnapshot.getId());
+    when(sentryStore.isAuthzPathsMappingEmpty()).thenReturn(false);
+    hmsFollower.run();
+    verify(sentryStore, times(0)).persistFullPathsImage(Mockito.anyMap(), Mockito.anyLong());
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(Mockito.anyLong());
+
+  }
+
+  @Test
+  public void testPersistAFullSnapshotWhenAuthzsnapshotIsEmptyAndHDFSSyncIsEnabled() throws Exception {
+    /*
+     * TEST CASE
+     *
+     * Simulates (by using mocks) the following:
+     *
+     * Disable HDFSSync before triggering a full snapshot
+     *
+     * HMS client always returns the paths image with the eventId == 1.
+     *
+     * On the 1st run:   Hdfs sync is disabled in sentry server
+     * Sentry notification table is empty, so this
+     * should not trigger a new full HMS snapshot request but should
+     * fetch all the HMS notifications and persist them.
+     *
+     * On the 2nd run: Just enable hdfs sync and a full snapshot should be triggered
+     * because MAuthzPathsMapping table is empty
+     *
+     */
+
+    disableHdfsSyncInSentry(configuration);
+
+    final long SENTRY_PROCESSED_EVENT_ID = SentryStore.EMPTY_NOTIFICATION_ID;
+    final long HMS_PROCESSED_EVENT_ID = 1L;
+
+    // Mock that returns a full snapshot
+    Map<String, Collection<String>> snapshotObjects = new HashMap<>();
+    snapshotObjects.put("db", Sets.newHashSet("/db"));
+    snapshotObjects.put("db.table", Sets.newHashSet("/db/table"));
+    PathsImage fullSnapshot = new PathsImage(snapshotObjects, HMS_PROCESSED_EVENT_ID, 1);
+
+    SentryHMSClient sentryHmsClient = Mockito.mock(SentryHMSClient.class);
+    when(sentryHmsClient.getFullSnapshot()).thenReturn(fullSnapshot);
+
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hmsConnectionMock, hiveInstance);
+    hmsFollower.setSentryHmsClient(sentryHmsClient);
+
+    // 1st run should get a full snapshot because hms notificaions is empty
+    // but it should never be persisted because HDFS sync is disabled
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(SENTRY_PROCESSED_EVENT_ID);
+    when(sentryStore.isHmsNotificationEmpty()).thenReturn(true);
+    hmsFollower.run();
+    // Since HDFS sync is disabled, fullsnapshot should not be fetched from HMS
+    verify(sentryStore, times(0)).persistFullPathsImage(
+        fullSnapshot.getPathImage(), fullSnapshot.getId());
+    verify(sentryStore, times(1)).getLastProcessedNotificationID();
+    // Making sure that HMS client is invoked to get all the notifications
+    // starting from event-id 0
+    verify(hmsClientMock, times(1)).getNextNotification(Mockito.eq(0L),
+            Mockito.eq(Integer.MAX_VALUE), Mockito.anyObject());
+
+    reset(sentryStore);
+
+    //Re-enable HDFS Sync and simply start the HMS follower thread, full snap shot
+    // should be triggered because MAuthzPathsMapping table is empty
+    enableHdfsSyncInSentry(configuration);
+
+    //Create a new hmsFollower instance since configuration is changing
+    hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hmsConnectionMock, hiveInstance);
+    hmsFollower.setSentryHmsClient(sentryHmsClient);
+
+
+    //Set last processed notification Id to match the full new value 1L
+    final long LATEST_EVENT_ID = 1L;
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(LATEST_EVENT_ID);
+    //Mock that sets isHmsNotificationEmpty to false
+    when(sentryStore.isHmsNotificationEmpty()).thenReturn(false);
+    // Mock that sets the current HMS notification ID. Set it to match
+    // last processed notification Id so that doesn't trigger a full snapshot
+    when(hmsClientMock.getCurrentNotificationEventId())
+        .thenReturn(new CurrentNotificationEventId(LATEST_EVENT_ID));
+    //Mock that sets getting next notification eve
+    when(hmsClientMock.getNextNotification(Mockito.eq(HMS_PROCESSED_EVENT_ID - 1), Mockito.eq(Integer.MAX_VALUE),
+        (NotificationFilter) Mockito.notNull()))
+        .thenReturn(new NotificationEventResponse(
+            Arrays.<NotificationEvent>asList(
+                new NotificationEvent(LATEST_EVENT_ID, 0, "", "")
+            )
+        ));
+    //Mock that sets isAuthzPathsSnapshotEmpty to true so trigger this particular test
+    when(sentryStore.isAuthzPathsSnapshotEmpty()).thenReturn(true);
+
+    hmsFollower.run();
+    verify(sentryStore, times(1)).persistFullPathsImage(
+        fullSnapshot.getPathImage(), fullSnapshot.getId());
+    verify(sentryStore, times(0)).setLastProcessedNotificationID(fullSnapshot.getId());
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(fullSnapshot.getId());
+
+  }
+
+  @Test
+  public void testDisablingAndEnablingHDFSSync() throws Exception {
+    /*
+     * TEST CASE
+     *
+     * Simulates (by using mocks) the following:
+     *
+     * Disable HDFSSync before and enable it later.
+     *
+     * HMS client always returns the paths image with the eventId == 1.
+     *
+     * On the 1st run:  Hdfs sync is disabled in sentry server.
+     * This should not trigger a new full HMS snapshot request but should
+     * fetch all the HMS notifications and persist them.
+     *
+     * On the 2nd run: Hdfs sync is enabled in sentry server
+      * Full snapshot should be fetched and persisted because MAuthzPathsMapping table is empty
+     *
+     * On 3rd run: Hdfs sync is disabled in sentry server.
+     * Sentry should remove the HMS path information(MAuthzPathsMapping and MSentryPathChange)
+     * but continue to process the notifications based on the information persisted in MSentryHmsNotification.
+     *
+     * on 4th run: Hdfs sync is enabled in sentry server
+     * Full snapshot should be fetched and persisted because MAuthzPathsMapping table is empty
+     *
+     */
+
+    disableHdfsSyncInSentry(configuration);
+
+    final long SENTRY_PROCESSED_EVENT_ID = SentryStore.EMPTY_NOTIFICATION_ID;
+    final long HMS_PROCESSED_EVENT_ID = 1L;
+
+    // Mock that returns a full snapshot
+    Map<String, Collection<String>> snapshotObjects = new HashMap<>();
+    snapshotObjects.put("db", Sets.newHashSet("/db"));
+    snapshotObjects.put("db.table", Sets.newHashSet("/db/table"));
+    PathsImage fullSnapshot = new PathsImage(snapshotObjects, HMS_PROCESSED_EVENT_ID, 1);
+
+    SentryHMSClient sentryHmsClient = Mockito.mock(SentryHMSClient.class);
+    when(sentryHmsClient.getFullSnapshot()).thenReturn(fullSnapshot);
+
+    NotificationEventResponse response = new NotificationEventResponse();
+
+    response.addToEvents(new NotificationEvent(1L, 0, "CREATE_DATABASE", ""));
+    response.addToEvents(new NotificationEvent(2L, 0, "CREATE_TABLE", ""));
+    response.addToEvents(new NotificationEvent(3L, 0, "ALTER_TABLE", ""));
+
+    when(hmsClientMock.getNextNotification(Mockito.eq(0L), Mockito.eq(Integer.MAX_VALUE),
+            Mockito.anyObject())).thenReturn(response);
+
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+            hmsConnectionMock, hiveInstance);
+    hmsFollower.setSentryHmsClient(sentryHmsClient);
+
+    // 1st run should not fetch full snapshot but should fetch notifications from 0
+    // and persists them
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(SENTRY_PROCESSED_EVENT_ID);
+    when(sentryStore.isHmsNotificationEmpty()).thenReturn(true);
+    hmsFollower.run();
+    verify(sentryStore, times(0)).persistFullPathsImage(
+            fullSnapshot.getPathImage(), fullSnapshot.getId());
+    verify(sentryStore, times(1)).clearHmsPathInformation();
+    // Making sure that HMS client is invoked to get all the notifications
+    // starting from event-id 0
+    verify(hmsClientMock, times(1)).getNextNotification(Mockito.eq(0L),
+            Mockito.eq(Integer.MAX_VALUE), Mockito.anyObject());
+    verify(sentryStore, times(1)).persistLastProcessedNotificationID(1L);
+    verify(sentryStore, times(1)).persistLastProcessedNotificationID(2L);
+    verify(sentryStore, times(1)).persistLastProcessedNotificationID(3L);
+
+    reset(sentryStore, hmsClientMock);
+
+    //Enable HDFS sync to make sure that Full snapshot is fetched from HMS and persisted.
+    enableHdfsSyncInSentry(configuration);
+    when(sentryStore.isHmsNotificationEmpty()).thenReturn(false);
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(HMS_PROCESSED_EVENT_ID);
+    when(sentryStore.isAuthzPathsSnapshotEmpty()).thenReturn(true);
+    // Mock that sets the current HMS notification ID. Set it to match
+    // last processed notification Id so that doesn't trigger a full snapshot
+    when(hmsClientMock.getCurrentNotificationEventId())
+            .thenReturn(new CurrentNotificationEventId(HMS_PROCESSED_EVENT_ID));
+    hmsFollower = new HMSFollower(configuration, sentryStore, null,
+            hmsConnectionMock, hiveInstance);
+    hmsFollower.setSentryHmsClient(sentryHmsClient);
+
+    // 2nd run get a full snapshot because there was no snapshot persisted before.
+    hmsFollower.run();
+    verify(sentryStore, times(0)).clearHmsPathInformation();
+    verify(sentryStore, times(1)).persistFullPathsImage(
+            fullSnapshot.getPathImage(), fullSnapshot.getId());
+    verify(sentryStore, times(0)).setLastProcessedNotificationID(fullSnapshot.getId());
+
+    reset(sentryStore, hmsClientMock);
+
+    disableHdfsSyncInSentry(configuration);
+    when(sentryStore.isHmsNotificationEmpty()).thenReturn(false);
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(HMS_PROCESSED_EVENT_ID);
+    when(sentryStore.isAuthzPathsSnapshotEmpty()).thenReturn(true);
+    // Mock that sets the current HMS notification ID. Set it to match
+    // last processed notification Id so that doesn't trigger a full snapshot
+    when(hmsClientMock.getCurrentNotificationEventId())
+            .thenReturn(new CurrentNotificationEventId(HMS_PROCESSED_EVENT_ID));
+
+    hmsFollower = new HMSFollower(configuration, sentryStore, null,
+            hmsConnectionMock, hiveInstance);
+    hmsFollower.setSentryHmsClient(sentryHmsClient);
+    // 3rd run
+    hmsFollower.run();
+    verify(sentryStore, times(0)).persistFullPathsImage(
+            fullSnapshot.getPathImage(), fullSnapshot.getId());
+    verify(sentryStore, times(1)).clearHmsPathInformation();
+    verify(sentryStore, times(0)).setLastProcessedNotificationID(Mockito.anyLong());
+    //Make sure that HMSFollower continues to fetch notifications based on persisted notifications.
+    verify(hmsClientMock, times(1)).getNextNotification(Mockito.eq(fullSnapshot.getId()-1),
+            Mockito.eq(Integer.MAX_VALUE), Mockito.anyObject());
+
+    reset(sentryStore, hmsClientMock);
+    enableHdfsSyncInSentry(configuration);
+    when(sentryStore.isHmsNotificationEmpty()).thenReturn(false);
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(HMS_PROCESSED_EVENT_ID);
+    when(sentryStore.isAuthzPathsSnapshotEmpty()).thenReturn(true);
+
+    hmsFollower = new HMSFollower(configuration, sentryStore, null,
+            hmsConnectionMock, hiveInstance);
+    hmsFollower.setSentryHmsClient(sentryHmsClient);
+    // 4th run
+    hmsFollower.run();
+    verify(sentryStore, times(0)).clearHmsPathInformation();
+    verify(sentryStore, times(1)).persistFullPathsImage(
+            fullSnapshot.getPathImage(), fullSnapshot.getId());
+    verify(sentryStore, times(0)).setLastProcessedNotificationID(fullSnapshot.getId());
+
+    reset(sentryStore, hmsClientMock);
+  }
+
+  @Test
+  public void testPersistAFullSnapshotWhenLastHmsNotificationIsLowerThanLastProcessed()
+      throws Exception {
+    /*
+     * TEST CASE
+     *
+     * Simulates (by using mocks) that Sentry already processed (and persisted) a notification
+     * with Id = 5, but the latest notification processed by the HMS is eventId = 1. So, an
+     * out-of-sync issue is happening on Sentry and HMS. This out-of-sync issue should trigger
+     * a new full HMS snapshot request with the same eventId = 1;
+     */
+
+    final long SENTRY_PROCESSED_EVENT_ID = 5L;
+    final long HMS_PROCESSED_EVENT_ID = 1L;
+
+    // Mock that returns a full snapshot
+    Map<String, Collection<String>> snapshotObjects = new HashMap<>();
+    snapshotObjects.put("db", Sets.newHashSet("/db"));
+    snapshotObjects.put("db.table", Sets.newHashSet("/db/table"));
+    PathsImage fullSnapshot = new PathsImage(snapshotObjects, HMS_PROCESSED_EVENT_ID, 1);
+
+    // Mock that returns the current HMS notification ID
+    when(hmsClientMock.getCurrentNotificationEventId())
+        .thenReturn(new CurrentNotificationEventId(fullSnapshot.getId()));
+
+    SentryHMSClient sentryHmsClient = Mockito.mock(SentryHMSClient.class);
+    when(sentryHmsClient.getFullSnapshot()).thenReturn(fullSnapshot);
+
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hmsConnectionMock, hiveInstance);
+    hmsFollower.setSentryHmsClient(sentryHmsClient);
+
+    // 1st run should get a full snapshot
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(SENTRY_PROCESSED_EVENT_ID);
+    when(sentryStore.isAuthzPathsMappingEmpty()).thenReturn(false);
+    hmsFollower.run();
+    verify(sentryStore, times(1)).persistFullPathsImage(Mockito.anyMap(), Mockito.anyLong());
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(Mockito.anyLong());
+
+    reset(sentryStore);
+
+    // 2nd run should not get a snapshot because is already processed
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(HMS_PROCESSED_EVENT_ID);
+    when(sentryStore.isAuthzPathsMappingEmpty()).thenReturn(false);
+    hmsFollower.run();
+    verify(sentryStore, times(0)).persistFullPathsImage(Mockito.anyMap(), Mockito.anyLong());
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(Mockito.anyLong());
+  }
+
+  @Test
+  public void testPersistAFullSnapshotWhenNextExpectedEventIsNotAvailable() throws Exception {
+    /*
+     * TEST CASE
+     *
+     * Simulates (by using mocks) that Sentry already processed (and persisted) a notification
+     * with Id = 1, and the latest notification processed by the HMS is eventId = 5. So, new
+     * notifications should be fetched.
+     *
+     * The number of expected notifications should be 4, but we simulate that we fetch only one
+     * notification with eventId = 5 causing an out-of-sync because the expected notificatoin
+     * should be 2. This out-of-sync should trigger a new full HMS snapshot request with the
+     * same eventId = 5.
+     */
+
+    final long SENTRY_PROCESSED_EVENT_ID = 1L;
+    final long HMS_PROCESSED_EVENT_ID = 5L;
+
+    // Mock that returns a full snapshot
+    Map<String, Collection<String>> snapshotObjects = new HashMap<>();
+    snapshotObjects.put("db", Sets.newHashSet("/db"));
+    snapshotObjects.put("db.table", Sets.newHashSet("/db/table"));
+    PathsImage fullSnapshot = new PathsImage(snapshotObjects, HMS_PROCESSED_EVENT_ID, 1);
+
+    // Mock that returns the current HMS notification ID
+    when(hmsClientMock.getCurrentNotificationEventId())
+        .thenReturn(new CurrentNotificationEventId(fullSnapshot.getId()));
+
+    SentryHMSClient sentryHmsClient = Mockito.mock(SentryHMSClient.class);
+    when(sentryHmsClient.getFullSnapshot()).thenReturn(fullSnapshot);
+
+    when(hmsClientMock.getNextNotification(Mockito.eq(SENTRY_PROCESSED_EVENT_ID - 1), Mockito.eq(Integer.MAX_VALUE),
+        (NotificationFilter) Mockito.notNull()))
+        .thenReturn(new NotificationEventResponse(
+            Arrays.<NotificationEvent>asList(
+                new NotificationEvent(fullSnapshot.getId(), 0, "", "")
+            )
+        ));
+
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hmsConnectionMock, hiveInstance);
+    hmsFollower.setSentryHmsClient(sentryHmsClient);
+
+    // 1st run should get a full snapshot
+    when(sentryStore.getLastProcessedNotificationID())
+        .thenReturn(SENTRY_PROCESSED_EVENT_ID);
+    when(sentryStore.isHmsNotificationEmpty()).thenReturn(false);
+    hmsFollower.run();
+    verify(sentryStore, times(1)).persistFullPathsImage(Mockito.anyMap(), Mockito.anyLong());
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(Mockito.anyLong());
+
+    reset(sentryStore);
+
+    // 2nd run should not get a snapshot because is already processed
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(HMS_PROCESSED_EVENT_ID);
+    when(sentryStore.isAuthzPathsMappingEmpty()).thenReturn(false);
+    hmsFollower.run();
+    verify(sentryStore, times(0)).persistFullPathsImage(Mockito.anyMap(), Mockito.anyLong());
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(Mockito.anyLong());
+  }
+
+  /**
+   * Test that HMSFollower uses the input authentication server name when it is not null
+   */
+  @Test
+  public void testInputConfigurationGetInputAuthServerName() {
+    Configuration sentryConfiguration = new Configuration();
+    HMSFollower hmsFollower = new HMSFollower(sentryConfiguration, sentryStore, null,
+        hiveConnectionFactory, hiveInstance);
+    String authServerName = hmsFollower.getAuthServerName();
+
+    Assert.assertEquals(true, authServerName.equals(hiveInstance));
+  }
+
+  /**
+   * Test that HMSFollower uses the default authentication server name when its constructor input
+   * value is null and the configuration does not configure AUTHZ_SERVER_NAME nor
+   * AUTHZ_SERVER_NAME_DEPRECATED
+   */
+  @Test
+  public void testNoConfigurationGetDefaultAuthServerName() {
+    Configuration sentryConfiguration = new Configuration();
+    HMSFollower hmsFollower = new HMSFollower(sentryConfiguration, sentryStore, null,
+        hiveConnectionFactory, null);
+    String authServerName = hmsFollower.getAuthServerName();
+
+    Assert.assertEquals(true, authServerName.equals(AuthzConfVars.AUTHZ_SERVER_NAME_DEPRECATED.getDefault()));
+  }
+
+  /**
+   * Test that HMSFollower uses the configured authentication server name when its constructor input
+   * value is null and the configuration contains configuration for AUTHZ_SERVER_NAME
+   */
+  @Test
+  public void testNewNameConfigurationGetAuthServerName() {
+    String serverName = "newServer";
+    Configuration sentryConfiguration = new Configuration();
+    sentryConfiguration.set(HiveAuthzConf.AuthzConfVars.AUTHZ_SERVER_NAME.getVar(), serverName);
+    HMSFollower hmsFollower = new HMSFollower(sentryConfiguration, sentryStore, null,
+        hiveConnectionFactory, null);
+    String authServerName = hmsFollower.getAuthServerName();
+
+    Assert.assertEquals(true, authServerName.equals(serverName));
+  }
+
+  /**
+   * Test that HMSFollower uses the configured deprecated authentication server name when its constructor input
+   * value is null and the configuration contains configuration for AUTHZ_SERVER_NAME_DEPRECATED
+   */
+  @Test
+  public void testOldNameConfigurationGetAuthServerName() {
+    String serverName = "oldServer";
+    Configuration sentryConfiguration = new Configuration();
+    sentryConfiguration.set(AuthzConfVars.AUTHZ_SERVER_NAME_DEPRECATED.getVar(), serverName);
+    HMSFollower hmsFollower = new HMSFollower(sentryConfiguration, sentryStore, null,
+        hiveConnectionFactory, null);
+    String authServerName = hmsFollower.getAuthServerName();
+
+    Assert.assertEquals(true, authServerName.equals(serverName));
+  }
+
+  /**
+   * Constructs create database event and makes sure that appropriate sentry store API's
+   * are invoke when the event is processed by hms follower.
+   *
+   * @throws Exception
+   */
+  @Test
+  public void testCreateDatabase() throws Exception {
+    String dbName = "db1";
+
+    // Create notification events
+    NotificationEvent notificationEvent = new NotificationEvent(1, 0,
+        EventMessage.EventType.CREATE_DATABASE.toString(),
+        messageFactory.buildCreateDatabaseMessage(new Database(dbName, null, "hdfs:///db1", null))
+            .toString());
+    List<NotificationEvent> events = new ArrayList<>();
+    events.add(notificationEvent);
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hiveConnectionFactory, hiveInstance);
+    hmsFollower.processNotifications(events);
+
+    TSentryAuthorizable authorizable = new TSentryAuthorizable(hiveInstance);
+    authorizable.setServer(hiveInstance);
+    authorizable.setDb("db1");
+
+    verify(sentryStore, times(1))
+        .dropPrivilege(authorizable, NotificationProcessor.getPermUpdatableOnDrop(authorizable));
+  }
+
+  /**
+   * Constructs drop database event and makes sure that appropriate sentry store API's
+   * are invoke when the event is processed by hms follower.
+   *
+   * @throws Exception
+   */
+  @Test
+  public void testDropDatabase() throws Exception {
+    String dbName = "db1";
+
+    // Create notification events
+    NotificationEvent notificationEvent = new NotificationEvent(1, 0,
+        EventMessage.EventType.DROP_DATABASE.toString(),
+        messageFactory.buildDropDatabaseMessage(new Database(dbName, null, "hdfs:///db1", null))
+            .toString());
+    List<NotificationEvent> events = new ArrayList<>();
+    events.add(notificationEvent);
+
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hiveConnectionFactory, hiveInstance);
+    hmsFollower.processNotifications(events);
+
+    TSentryAuthorizable authorizable = new TSentryAuthorizable(hiveInstance);
+    authorizable.setServer(hiveInstance);
+    authorizable.setDb("db1");
+
+    verify(sentryStore, times(1))
+        .dropPrivilege(authorizable, NotificationProcessor.getPermUpdatableOnDrop(authorizable));
+  }
+
+  /**
+   * Constructs create table event and makes sure that appropriate sentry store API's
+   * are invoke when the event is processed by hms follower.
+   *
+   * @throws Exception
+   */
+  @Test
+  public void testCreateTable() throws Exception {
+    String dbName = "db1";
+    String tableName = "table1";
+
+    // Create notification events
+    StorageDescriptor sd = new StorageDescriptor();
+    sd.setLocation("hdfs:///db1.db/table1");
+    NotificationEvent notificationEvent = new NotificationEvent(1, 0,
+        EventMessage.EventType.CREATE_TABLE.toString(),
+        messageFactory.buildCreateTableMessage(
+            new Table(tableName, dbName, null, 0, 0, 0, sd, null, null, null, null, null),
+            Collections.emptyIterator()).toString());
+    List<NotificationEvent> events = new ArrayList<>();
+    events.add(notificationEvent);
+
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hiveConnectionFactory, hiveInstance);
+    hmsFollower.processNotifications(events);
+
+    TSentryAuthorizable authorizable = new TSentryAuthorizable(hiveInstance);
+    authorizable.setServer(hiveInstance);
+    authorizable.setDb("db1");
+    authorizable.setTable(tableName);
+
+    verify(sentryStore, times(1))
+        .dropPrivilege(authorizable, NotificationProcessor.getPermUpdatableOnDrop(authorizable));
+  }
+
+  /**
+   * Constructs drop table event and makes sure that appropriate sentry store API's
+   * are invoke when the event is processed by hms follower.
+   *
+   * @throws Exception
+   */
+  @Test
+  public void testDropTable() throws Exception {
+    String dbName = "db1";
+    String tableName = "table1";
+
+    // Create notification events
+    StorageDescriptor sd = new StorageDescriptor();
+    sd.setLocation("hdfs:///db1.db/table1");
+    NotificationEvent notificationEvent = new NotificationEvent(1, 0,
+        EventMessage.EventType.DROP_TABLE.toString(),
+        messageFactory.buildDropTableMessage(
+            new Table(tableName, dbName, null, 0, 0, 0, sd, null, null, null, null, null))
+            .toString());
+    List<NotificationEvent> events = new ArrayList<>();
+    events.add(notificationEvent);
+
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hiveConnectionFactory, hiveInstance);
+    hmsFollower.processNotifications(events);
+
+    TSentryAuthorizable authorizable = new TSentryAuthorizable(hiveInstance);
+    authorizable.setServer(hiveInstance);
+    authorizable.setDb("db1");
+    authorizable.setTable(tableName);
+
+    verify(sentryStore, times(1))
+        .dropPrivilege(authorizable, NotificationProcessor.getPermUpdatableOnDrop(authorizable));
+  }
+
+  /**
+   * Constructs rename table event and makes sure that appropriate sentry store API's
+   * are invoke when the event is processed by hms follower.
+   *
+   * @throws Exception
+   */
+  @Test
+  public void testRenameTable() throws Exception {
+    String dbName = "db1";
+    String tableName = "table1";
+
+    String newDbName = "db1";
+    String newTableName = "table2";
+
+    // Create notification events
+    StorageDescriptor sd = new StorageDescriptor();
+    sd.setLocation("hdfs:///db1.db/table1");
+    NotificationEvent notificationEvent = new NotificationEvent(1, 0,
+        EventMessage.EventType.ALTER_TABLE.toString(),
+        messageFactory.buildAlterTableMessage(
+            new Table(tableName, dbName, null, 0, 0, 0, sd, null, null, null, null, null),
+            new Table(newTableName, newDbName, null, 0, 0, 0, sd, null, null, null, null, null))
+            .toString());
+    notificationEvent.setDbName(newDbName);
+    notificationEvent.setTableName(newTableName);
+    List<NotificationEvent> events = new ArrayList<>();
+    events.add(notificationEvent);
+
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hiveConnectionFactory, hiveInstance);
+    hmsFollower.processNotifications(events);
+
+    TSentryAuthorizable authorizable = new TSentryAuthorizable(hiveInstance);
+    authorizable.setServer(hiveInstance);
+    authorizable.setDb(dbName);
+    authorizable.setTable(tableName);
+
+    TSentryAuthorizable newAuthorizable = new TSentryAuthorizable(hiveInstance);
+    authorizable.setServer(hiveInstance);
+    newAuthorizable.setDb(newDbName);
+    newAuthorizable.setTable(newTableName);
+
+    verify(sentryStore, times(1)).renamePrivilege(authorizable, newAuthorizable,
+        NotificationProcessor.getPermUpdatableOnRename(authorizable, newAuthorizable));
+  }
+
+
+  @Ignore
+  /**
+   * Constructs a bunch of events and passed to processor of hms follower. One of those is alter
+   * partition event with out actually changing anything(invalid event). Idea is to make sure that
+   * hms follower calls appropriate sentry store API's for the events processed by hms follower
+   * after processing the invalid alter partition event.
+   *
+   * @throws Exception
+   */
+  @Test
+  public void testAlterPartitionWithInvalidEvent() throws Exception {
+    String dbName = "db1";
+    String tableName1 = "table1";
+    String tableName2 = "table2";
+    long inputEventId = 1;
+    List<NotificationEvent> events = new ArrayList<>();
+    NotificationEvent notificationEvent;
+    List<FieldSchema> partCols;
+    StorageDescriptor sd;
+    Mockito.doNothing().when(sentryStore).persistLastProcessedNotificationID(Mockito.anyLong());
+    //noinspection unchecked
+    Mockito.doNothing().when(sentryStore).addAuthzPathsMapping(Mockito.anyString(),
+        Mockito.anyCollection(), Mockito.any(UniquePathsUpdate.class));
+
+    Configuration configuration = new Configuration();
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hiveConnectionFactory, hiveInstance);
+    // Create a table
+    sd = new StorageDescriptor();
+    sd.setLocation("hdfs://db1.db/table1");
+    partCols = new ArrayList<>();
+    partCols.add(new FieldSchema("ds", "string", ""));
+    Table table = new Table(tableName1, dbName, null, 0, 0, 0, sd, partCols, null, null, null,
+        null);
+    notificationEvent = new NotificationEvent(inputEventId, 0,
+        EventMessage.EventType.CREATE_TABLE.toString(),
+        messageFactory.buildCreateTableMessage(table, Collections.emptyIterator()).toString());
+    notificationEvent.setDbName(dbName);
+    notificationEvent.setTableName(tableName1);
+    events.add(notificationEvent);
+    inputEventId += 1;
+    // Process the notification
+    hmsFollower.processNotifications(events);
+    // Make sure that addAuthzPathsMapping was invoked once to handle CREATE_TABLE notification
+    // and persistLastProcessedNotificationID was not invoked.
+    //noinspection unchecked
+    verify(sentryStore, times(1)).addAuthzPathsMapping(Mockito.anyString(),
+        Mockito.anyCollection(), Mockito.any(UniquePathsUpdate.class));
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(Mockito.anyLong());
+    reset(sentryStore);
+    events.clear();
+
+    // Create a partition
+    List<Partition> partitions = new ArrayList<>();
+    StorageDescriptor invalidSd = new StorageDescriptor();
+    invalidSd.setLocation(null);
+    Partition partition = new Partition(Collections.singletonList("today"), dbName, tableName1,
+        0, 0, sd, null);
+    partitions.add(partition);
+    notificationEvent = new NotificationEvent(inputEventId, 0, EventType.ADD_PARTITION.toString(),
+       messageFactory.buildAddPartitionMessage(table, partitions.iterator(), Collections.emptyIterator()).toString());
+    notificationEvent.setDbName(dbName);
+    notificationEvent.setTableName(tableName1);
+    events.add(notificationEvent);
+    inputEventId += 1;
+    //Process the notification
+    hmsFollower.processNotifications(events);
+    // Make sure that addAuthzPathsMapping was invoked once to handle ADD_PARTITION notification
+    // and persistLastProcessedNotificationID was not invoked.
+    //noinspection unchecked
+    verify(sentryStore, times(1)).addAuthzPathsMapping(Mockito.anyString(),
+        Mockito.anyCollection(), Mockito.any(UniquePathsUpdate.class));
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(Mockito.anyLong());
+    reset(sentryStore);
+    events.clear();
+
+    // Create a alter notification with out actually changing anything.
+    // This is an invalid event and should be processed by sentry store.
+    // Event Id should be explicitly persisted using persistLastProcessedNotificationID
+    notificationEvent = new NotificationEvent(inputEventId, 0, EventType.ALTER_PARTITION.toString(),
+        messageFactory.buildAlterPartitionMessage(table, partition, partition).toString());
+    notificationEvent.setDbName(dbName);
+    notificationEvent.setTableName(tableName1);
+    events.add(notificationEvent);
+    inputEventId += 1;
+    // Process the notification
+    hmsFollower.processNotifications(events);
+    // Make sure that persistLastProcessedNotificationID is invoked explicitly.
+    verify(sentryStore, times(1)).persistLastProcessedNotificationID(inputEventId - 1);
+    reset(sentryStore);
+    events.clear();
+
+    // Create a alter notification with some actual change.
+    sd = new StorageDescriptor();
+    sd.setLocation("hdfs://user/hive/warehouse/db1.db/table1");
+    Partition updatedPartition = new Partition(partition);
+    updatedPartition.setSd(sd);
+    notificationEvent = new NotificationEvent(inputEventId, 0, EventType.ALTER_PARTITION.toString(),
+      messageFactory.buildAlterPartitionMessage(table, partition, updatedPartition).toString());
+    notificationEvent.setDbName(dbName);
+    notificationEvent.setTableName(tableName1);
+    events.add(notificationEvent);
+    inputEventId += 1;
+    // Process the notification
+    hmsFollower.processNotifications(events);
+    // Make sure that updateAuthzPathsMapping was invoked once to handle ALTER_PARTITION
+    // notification and persistLastProcessedNotificationID was not invoked.
+    verify(sentryStore, times(1)).updateAuthzPathsMapping(Mockito.anyString(),
+        Mockito.anyString(), Mockito.anyString(), Mockito.any(UniquePathsUpdate.class));
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(inputEventId - 1);
+    reset(sentryStore);
+    events.clear();
+
+    // Create a table
+    sd = new StorageDescriptor();
+    sd.setLocation("hdfs://db1.db/table2");
+    partCols = new ArrayList<>();
+    partCols.add(new FieldSchema("ds", "string", ""));
+    Table table1 = new Table(tableName2, dbName, null, 0, 0, 0, sd, partCols, null, null, null,
+        null);
+    notificationEvent = new NotificationEvent(inputEventId, 0,
+        EventMessage.EventType.CREATE_TABLE.toString(),
+        messageFactory.buildCreateTableMessage(table1, Collections.emptyIterator()).toString());
+    notificationEvent.setDbName(dbName);
+    notificationEvent.setTableName(tableName2);
+    events.add(notificationEvent);
+    // Process the notification
+    hmsFollower.processNotifications(events);
+    // Make sure that addAuthzPathsMapping was invoked once to handle CREATE_TABLE notification
+    // and persistLastProcessedNotificationID was not invoked.
+    //noinspection unchecked
+    verify(sentryStore, times(1)).addAuthzPathsMapping(Mockito.anyString(),
+        Mockito.anyCollection(), Mockito.any(UniquePathsUpdate.class));
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(Mockito.anyLong());
+  }
+
+  /**
+   * Constructs a bunch of events and passed to processor of hms follower. One of those is alter
+   * table event with out actually changing anything(invalid event). Idea is to make sure that
+   * hms follower calls appropriate sentry store API's for the events processed by hms follower
+   * after processing the invalid alter table event.
+   *
+   * @throws Exception
+   */
+  @Test
+  public void testAlterTableWithInvalidEvent() throws Exception {
+    String dbName = "db1";
+    String tableName1 = "table1";
+    String tableName2 = "table2";
+    long inputEventId = 1;
+    List<NotificationEvent> events = new ArrayList<>();
+    NotificationEvent notificationEvent;
+    List<FieldSchema> partCols;
+    StorageDescriptor sd;
+    Mockito.doNothing().when(sentryStore).persistLastProcessedNotificationID(Mockito.anyLong());
+    //noinspection unchecked
+    Mockito.doNothing().when(sentryStore).addAuthzPathsMapping(Mockito.anyString(),
+        Mockito.anyCollection(), Mockito.any(UniquePathsUpdate.class));
+
+    Configuration configuration = new Configuration();
+    // enable HDFS sync, so perm and path changes will be saved into DB
+    enableHdfsSyncInSentry(configuration);
+
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hiveConnectionFactory, hiveInstance);
+
+    // Create a table
+    sd = new StorageDescriptor();
+    sd.setLocation("hdfs://db1.db/table1");
+    partCols = new ArrayList<>();
+    partCols.add(new FieldSchema("ds", "string", ""));
+    Table table = new Table(tableName1, dbName, null, 0, 0, 0, sd, partCols, null, null, null,
+        null);
+    notificationEvent = new NotificationEvent(inputEventId, 0,
+        EventMessage.EventType.CREATE_TABLE.toString(),
+        messageFactory.buildCreateTableMessage(table, Collections.emptyIterator()).toString());
+    notificationEvent.setDbName(dbName);
+    notificationEvent.setTableName(tableName1);
+    events.add(notificationEvent);
+    inputEventId += 1;
+    // Process the notification
+    hmsFollower.processNotifications(events);
+    // Make sure that addAuthzPathsMapping was invoked once to handle CREATE_TABLE notification
+    // and persistLastProcessedNotificationID was not invoked.
+    //noinspection unchecked
+    verify(sentryStore, times(1)).addAuthzPathsMapping(Mockito.anyString(),
+        Mockito.anyCollection(), Mockito.any(UniquePathsUpdate.class));
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(Mockito.anyLong());
+    reset(sentryStore);
+    events.clear();
+
+    // Create alter table notification with out actually changing anything.
+    // This notification should not be processed by sentry server
+    // Notification should be persisted explicitly
+    notificationEvent = new NotificationEvent(1, 0,
+        EventMessage.EventType.ALTER_TABLE.toString(),
+        messageFactory.buildAlterTableMessage(
+            new Table(tableName1, dbName, null, 0, 0, 0, sd, null, null, null, null, null),
+            new Table(tableName1, dbName, null, 0, 0, 0, sd, null, null, null, null, null))
+            .toString());
+    notificationEvent.setDbName(dbName);
+    notificationEvent.setTableName(tableName1);
+    events = new ArrayList<>();
+    events.add(notificationEvent);
+    inputEventId += 1;
+    // Process the notification
+    hmsFollower.processNotifications(events);
+    // Make sure that renameAuthzObj and deleteAuthzPathsMapping were  not invoked
+    // to handle CREATE_TABLE notification
+    // and persistLastProcessedNotificationID is explicitly invoked
+    verify(sentryStore, times(0)).renameAuthzObj(Mockito.anyString(), Mockito.anyString(),
+        Mockito.any(UniquePathsUpdate.class));
+    //noinspection unchecked
+    verify(sentryStore, times(0)).deleteAuthzPathsMapping(Mockito.anyString(),
+        Mockito.anyCollection(), Mockito.any(UniquePathsUpdate.class));
+    verify(sentryStore, times(1)).persistLastProcessedNotificationID(Mockito.anyLong());
+    reset(sentryStore);
+    events.clear();
+
+    // Create a table
+    sd = new StorageDescriptor();
+    sd.setLocation("hdfs://db1.db/table2");
+    partCols = new ArrayList<>();
+    partCols.add(new FieldSchema("ds", "string", ""));
+    Table table1 = new Table(tableName2, dbName, null, 0, 0, 0, sd, partCols, null, null, null,
+        null);
+    notificationEvent = new NotificationEvent(inputEventId, 0,
+        EventMessage.EventType.CREATE_TABLE.toString(),
+        messageFactory.buildCreateTableMessage(table1, Collections.emptyIterator()).toString());
+    notificationEvent.setDbName(dbName);
+    notificationEvent.setTableName(tableName2);
+    events.add(notificationEvent);
+    // Process the notification
+    hmsFollower.processNotifications(events);
+    // Make sure that addAuthzPathsMapping was invoked once to handle CREATE_TABLE notification
+    // and persistLastProcessedNotificationID was not invoked.
+    //noinspection unchecked
+    verify(sentryStore, times(1)).addAuthzPathsMapping(Mockito.anyString(),
+        Mockito.anyCollection(), Mockito.any(UniquePathsUpdate.class));
+    verify(sentryStore, times(0)).persistLastProcessedNotificationID(Mockito.anyLong());
+  }
+
+  /**
+   * Constructs a two events and passed to processor of hms follower. First one being create table
+   * event with location information(Invalid Event). Idea is to make sure that hms follower calls
+   * appropriate sentry store API's for the event processed by hms follower after processing the
+   * invalid create table event.
+   *
+   * @throws Exception
+   */
+  @Test
+  public void testCreateTableAfterInvalidEvent() throws Exception {
+    String dbName = "db1";
+    String tableName = "table1";
+    long inputEventId = 1;
+
+    Mockito.doNothing().when(sentryStore).persistLastProcessedNotificationID(Mockito.anyLong());
+    //noinspection unchecked
+    Mockito.doNothing().when(sentryStore)
+        .addAuthzPathsMapping(Mockito.anyString(), Mockito.anyCollection(),
+            Mockito.any(UniquePathsUpdate.class));
+
+    // Create invalid notification event. The location of the storage descriptor is null, which is invalid for creating table
+    StorageDescriptor invalidSd = new StorageDescriptor();
+    invalidSd.setLocation(null);
+    NotificationEvent invalidNotificationEvent = new NotificationEvent(inputEventId, 0,
+        EventMessage.EventType.CREATE_TABLE.toString(),
+        messageFactory.buildCreateTableMessage(
+            new Table(tableName, dbName, null, 0, 0, 0, invalidSd, null, null, null, null, null),
+            Collections.emptyIterator()).toString());
+
+    // Create valid notification event
+    StorageDescriptor sd = new StorageDescriptor();
+    sd.setLocation("hdfs://db1.db/table1");
+    inputEventId += 1;
+    NotificationEvent notificationEvent = new NotificationEvent(inputEventId, 0,
+        EventMessage.EventType.CREATE_TABLE.toString(),
+        messageFactory.buildCreateTableMessage(
+            new Table(tableName, dbName, null, 0, 0, 0, sd, null, null, null, null, null),
+            Collections.emptyIterator()).toString());
+    List<NotificationEvent> events = new ArrayList<>();
+    events.add(invalidNotificationEvent);
+    events.add(notificationEvent);
+
+    Configuration configuration = new Configuration();
+    enableHdfsSyncInSentry(configuration);
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hiveConnectionFactory, hiveInstance);
+    hmsFollower.processNotifications(events);
+
+    // invalid event updates notification ID directly
+    verify(sentryStore, times(1)).persistLastProcessedNotificationID(inputEventId - 1);
+
+    // next valid event update path, which updates notification ID
+    //noinspection unchecked
+    verify(sentryStore, times(1)).addAuthzPathsMapping(Mockito.anyString(), Mockito.anyCollection(),
+        Mockito.any(UniquePathsUpdate.class));
+  }
+
+  @Test
+  public void testNoHdfsNoPersistAFullSnapshot() throws Exception {
+
+     // TEST CASE
+     //
+     // Simulates (by using mocks) that Sentry has not processed any notifications.
+     // Test makes sure that this does not trigger a full snapshot and also makes sure that
+     // HMSFollower tries to fetch all notifications from HMS.
+
+
+    final long SENTRY_PROCESSED_EVENT_ID = SentryStore.EMPTY_NOTIFICATION_ID;
+    final long HMS_PROCESSED_EVENT_ID = 1L;
+
+    NotificationEventResponse response = new NotificationEventResponse();
+
+    response.addToEvents(new NotificationEvent(1L, 0, "CREATE_DATABASE", ""));
+    response.addToEvents(new NotificationEvent(1L, 0, "CREATE_TABLE", ""));
+    response.addToEvents(new NotificationEvent(2L, 0, "ALTER_TABLE", ""));
+
+    // Mock that returns the current HMS notification ID
+    when(hmsClientMock.getCurrentNotificationEventId())
+        .thenReturn(new CurrentNotificationEventId(HMS_PROCESSED_EVENT_ID));
+
+    when(hmsClientMock.getNextNotification(Mockito.eq(0L), Mockito.eq(Integer.MAX_VALUE),
+            Mockito.anyObject())).thenReturn(response);
+
+    SentryHMSClient sentryHmsClient = Mockito.mock(SentryHMSClient.class);
+   // when(sentryHmsClient.getFullSnapshot()).thenReturn(fullSnapshot);
+
+    Configuration configuration = new Configuration();
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hmsConnectionMock, hiveInstance);
+    hmsFollower.setSentryHmsClient(sentryHmsClient);
+
+    // 1st run should get a full snapshot because AuthzPathsMapping is empty
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(SENTRY_PROCESSED_EVENT_ID);
+    when(sentryStore.isAuthzPathsMappingEmpty()).thenReturn(false);
+    when(sentryStore.isHmsNotificationEmpty()).thenReturn(true);
+    hmsFollower.run();
+    verify(sentryStore, times(0)).persistFullPathsImage(Mockito.anyMap(), Mockito.anyLong());
+    verify(sentryStore, times(0)).isAuthzPathsMappingEmpty();
+    verify(hmsClientMock, times(1)).getNextNotification(Mockito.eq(0L),
+            Mockito.eq(Integer.MAX_VALUE), Mockito.anyObject());
+    verify(sentryStore, times(3)).persistLastProcessedNotificationID(Mockito.anyLong());
+  }
+
+  /**
+   * Tests the out-of-sync scenario when HDFS sync is disabled to make sure that
+   * HMSFollower starting fetching notifications from beginning after out-of-sync
+   * is detected.
+   * @throws Exception
+   */
+  @Test
+  public void testNoHdfsOutofSync() throws Exception {
+
+    // TEST CASE
+    //
+    // Simulates (by using mocks) that Sentry is out-of-sync with sentry
+
+    final long SENTRY_PROCESSED_EVENT_ID = SentryStore.EMPTY_NOTIFICATION_ID;
+
+    NotificationEventResponse response = new NotificationEventResponse();
+
+    response.addToEvents(new NotificationEvent(1L, 0, "CREATE_DATABASE", ""));
+    response.addToEvents(new NotificationEvent(2L, 0, "CREATE_TABLE", ""));
+    response.addToEvents(new NotificationEvent(3L, 0, "ALTER_TABLE", ""));
+
+    // Mock that returns the current HMS notification ID
+    when(hmsClientMock.getCurrentNotificationEventId())
+            .thenReturn(new CurrentNotificationEventId(3L));
+
+    when(hmsClientMock.getNextNotification(Mockito.eq(0L), Mockito.eq(Integer.MAX_VALUE),
+            Mockito.anyObject())).thenReturn(response);
+
+    SentryHMSClient sentryHmsClient = Mockito.mock(SentryHMSClient.class);
+
+    Configuration configuration = new Configuration();
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+            hmsConnectionMock, hiveInstance);
+    hmsFollower.setSentryHmsClient(sentryHmsClient);
+
+    // 1st run should not fetch t he full snapshot but should fetch all the notifications
+    // from HMS.
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(SENTRY_PROCESSED_EVENT_ID);
+    when(sentryStore.isAuthzPathsMappingEmpty()).thenReturn(false);
+    when(sentryStore.isHmsNotificationEmpty()).thenReturn(true);
+    hmsFollower.run();
+    verify(sentryStore, times(0)).persistFullPathsImage(Mockito.anyMap(), Mockito.anyLong());
+    verify(sentryStore, times(0)).isAuthzPathsMappingEmpty();
+    verify(hmsClientMock, times(1)).getNextNotification(Mockito.eq(0L),
+            Mockito.eq(Integer.MAX_VALUE), Mockito.anyObject());
+    verify(sentryStore, times(3)).persistLastProcessedNotificationID(Mockito.anyLong());
+    reset(sentryStore, hmsClientMock);
+
+    //Update the mock so that it returns the max(event-id) that was fetched in previous run
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(3L);
+    // Mock HMSClient so that it returns appropriate event-id
+    when(hmsClientMock.getCurrentNotificationEventId())
+            .thenReturn(new CurrentNotificationEventId(3L));
+
+    //2nd run
+    hmsFollower.run();
+    // Verify that HMSFollower starting fetching the notifications beyond what it already processed.
+    verify(hmsClientMock, times(1)).getNextNotification(Mockito.eq(3L-1),
+            Mockito.eq(Integer.MAX_VALUE), Mockito.anyObject());
+
+
+    // Mock that returns the current HMS notification ID which is less than what
+    // sentry already processed.
+    when(hmsClientMock.getCurrentNotificationEventId())
+            .thenReturn(new CurrentNotificationEventId(1L));
+    //Update the mock so that it returns the max(event-id) that was fetched in previous run
+    when(sentryStore.getLastProcessedNotificationID()).thenReturn(0L);
+
+    // 3rd run
+    hmsFollower.syncupWithHms(3L);
+    verify(hmsClientMock, times(1)).getNextNotification(Mockito.eq(0L),
+            Mockito.eq(Integer.MAX_VALUE), Mockito.anyObject());
+
+
+  }
+
+  @Test
+  public void testNoHdfsSyncAlterTableIsPersisted() throws Exception {
+    String dbName = "db1";
+    String tableName = "table1";
+    String newDbName = "db1";
+    String newTableName = "table2";
+
+    // Create notification events
+    StorageDescriptor sd = new StorageDescriptor();
+    sd.setLocation("hdfs:///db1.db/table1");
+    NotificationEvent notificationEvent = new NotificationEvent(1, 0,
+        EventMessage.EventType.ALTER_TABLE.toString(),
+        messageFactory.buildAlterTableMessage(
+            new Table(tableName, dbName, null, 0, 0, 0, sd, null, null, null, null, null),
+            new Table(newTableName, newDbName, null, 0, 0, 0, sd, null, null, null, null, null))
+            .toString());
+    notificationEvent.setDbName(newDbName);
+    notificationEvent.setTableName(newTableName);
+    List<NotificationEvent> events = new ArrayList<>();
+    events.add(notificationEvent);
+
+    Configuration configuration = new Configuration();
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        hiveConnectionFactory, hiveInstance);
+    hmsFollower.processNotifications(events);
+
+    TSentryAuthorizable authorizable = new TSentryAuthorizable(hiveInstance);
+    authorizable.setServer(hiveInstance);
+    authorizable.setDb(dbName);
+    authorizable.setTable(tableName);
+
+    TSentryAuthorizable newAuthorizable = new TSentryAuthorizable(hiveInstance);
+    authorizable.setServer(hiveInstance);
+    newAuthorizable.setDb(newDbName);
+    newAuthorizable.setTable(newTableName);
+
+    verify(sentryStore, times(1)).renamePrivilege(authorizable, newAuthorizable,
+        NotificationProcessor.getPermUpdatableOnRename(authorizable, newAuthorizable));
+  }
+}

http://git-wip-us.apache.org/repos/asf/sentry/blob/7db84b2f/sentry-service/sentry-service-server/src/test/java/org/apache/sentry/provider/db/service/persistent/TestHMSFollowerSentryStoreIntegration.java
----------------------------------------------------------------------
diff --git a/sentry-service/sentry-service-server/src/test/java/org/apache/sentry/provider/db/service/persistent/TestHMSFollowerSentryStoreIntegration.java b/sentry-service/sentry-service-server/src/test/java/org/apache/sentry/provider/db/service/persistent/TestHMSFollowerSentryStoreIntegration.java
new file mode 100644
index 0000000..4e8a2e6
--- /dev/null
+++ b/sentry-service/sentry-service-server/src/test/java/org/apache/sentry/provider/db/service/persistent/TestHMSFollowerSentryStoreIntegration.java
@@ -0,0 +1,256 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.sentry.provider.db.service.persistent;
+
+import static org.apache.sentry.binding.hive.conf.HiveAuthzConf.AuthzConfVars.AUTHZ_SERVER_NAME;
+
+import com.google.common.io.Files;
+import java.io.File;
+import org.apache.commons.io.FileUtils;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hive.conf.HiveConf;
+import org.apache.hadoop.hive.metastore.api.*;
+import org.apache.hadoop.security.alias.CredentialProvider;
+import org.apache.hadoop.security.alias.CredentialProviderFactory;
+import org.apache.hadoop.security.alias.UserProvider;
+import org.apache.hadoop.hive.metastore.messaging.EventMessage;
+import org.apache.hadoop.hive.metastore.messaging.EventMessage.EventType;
+import org.apache.sentry.binding.metastore.messaging.json.SentryJSONMessageFactory;
+
+import org.apache.sentry.api.service.thrift.TSentryPrivilege;
+import org.apache.sentry.service.thrift.HiveSimpleConnectionFactory;
+import org.apache.sentry.provider.file.PolicyFile;
+import org.apache.sentry.service.common.ServiceConstants.ServerConfig;
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Test integration of HMSFollower with SentryStore
+ */
+public class TestHMSFollowerSentryStoreIntegration {
+
+  // SentryStore related member
+  private static File dataDir;
+  private static SentryStore sentryStore;
+  private static String[] adminGroups = { "adminGroup1" };
+  private static PolicyFile policyFile;
+  private static File policyFilePath;
+  private static Configuration conf = null;
+  private static char[] passwd = new char[] { '1', '2', '3'};
+  private static String dbName1 = "db1";
+  private static String tableName1 = "table1";
+  private static String serverName1 = "server1";
+
+  // HMSFollower related member
+  SentryJSONMessageFactory messageFactory = new SentryJSONMessageFactory();
+  final static String hiveInstance = serverName1;
+
+
+  // SentryStore related
+  @BeforeClass
+  public static void setup() throws Exception {
+    conf = new Configuration(false);
+    final String ourUrl = UserProvider.SCHEME_NAME + ":///";
+    conf.set(CredentialProviderFactory.CREDENTIAL_PROVIDER_PATH, ourUrl);
+
+    // THis should be a UserGroupInformation provider
+    CredentialProvider provider = CredentialProviderFactory.getProviders(conf).get(0);
+
+    // The user credentials are stored as a static variable by UserGrouoInformation provider.
+    // We need to only set the password the first time, an attempt to set it for the second
+    // time fails with an exception.
+    if(provider.getCredentialEntry(ServerConfig.SENTRY_STORE_JDBC_PASS) == null) {
+      provider.createCredentialEntry(ServerConfig.SENTRY_STORE_JDBC_PASS, passwd);
+      provider.flush();
+    }
+
+    dataDir = new File(Files.createTempDir(), "sentry_policy_db");
+    conf.set(ServerConfig.SENTRY_VERIFY_SCHEM_VERSION, "false");
+    conf.set(ServerConfig.SENTRY_STORE_JDBC_URL,
+        "jdbc:derby:;databaseName=" + dataDir.getPath() + ";create=true");
+    conf.set(ServerConfig.SENTRY_STORE_JDBC_PASS, "dummy");
+    conf.setStrings(ServerConfig.ADMIN_GROUPS, adminGroups);
+    conf.set(ServerConfig.SENTRY_STORE_GROUP_MAPPING,
+        ServerConfig.SENTRY_STORE_LOCAL_GROUP_MAPPING);
+    policyFilePath = new File(dataDir, "local_policy_file.ini");
+    conf.set(ServerConfig.SENTRY_STORE_GROUP_MAPPING_RESOURCE,
+        policyFilePath.getPath());
+    conf.setInt(ServerConfig.SENTRY_STORE_TRANSACTION_RETRY, 10);
+
+  }
+
+  @Before
+  public void before() throws Exception {
+    sentryStore = new SentryStore(conf);
+    sentryStore.setPersistUpdateDeltas(true);
+    policyFile = new PolicyFile();
+    String adminUser = "g1";
+    addGroupsToUser(adminUser, adminGroups);
+    writePolicyFile();
+  }
+
+  @After
+  public void after() {
+    if (sentryStore != null) {
+      sentryStore.clearAllTables();
+      sentryStore.stop();
+    }
+  }
+
+  @AfterClass
+  public static void teardown() {
+
+    if (dataDir != null) {
+      FileUtils.deleteQuietly(dataDir);
+    }
+  }
+
+  protected static void addGroupsToUser(String user, String... groupNames) {
+    policyFile.addGroupsToUser(user, groupNames);
+  }
+
+  protected static void writePolicyFile() throws Exception {
+    policyFile.write(policyFilePath);
+  }
+
+  /**
+   * Test that SentryStore droppes the permission associated with the table when HMSFollower
+   * processes the drop table event
+   * @throws Exception
+   */
+  @Test
+  public void testDropTableDropRelatedPermission() throws Exception {
+    String serverName = "server1";
+
+    // create HMSFollower
+    Configuration configuration = new Configuration();
+    configuration.set(AUTHZ_SERVER_NAME.getVar(), serverName);
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+      new HiveSimpleConnectionFactory(conf, new HiveConf()), null);
+
+    // configure permission of the table
+    String roleName1 = "list-privs-r1";
+    String grantor = "g1";
+    sentryStore.createSentryRole(roleName1);
+
+    TSentryPrivilege privilege_tbl1 = new TSentryPrivilege();
+    privilege_tbl1.setPrivilegeScope("TABLE");
+    privilege_tbl1.setServerName(serverName);
+    privilege_tbl1.setDbName(dbName1);
+    privilege_tbl1.setTableName(tableName1);
+    privilege_tbl1.setCreateTime(System.currentTimeMillis());
+
+    TSentryPrivilege privilege1 = new TSentryPrivilege(privilege_tbl1);
+    privilege1.setAction("SELECT");
+
+    TSentryPrivilege privilege1_2 = new TSentryPrivilege(privilege_tbl1);
+    privilege1_2.setAction("INSERT");
+    TSentryPrivilege privilege1_3 = new TSentryPrivilege(privilege_tbl1);
+    privilege1_3.setAction("*");
+
+    TSentryPrivilege privilege_server = new TSentryPrivilege();
+    privilege_server.setPrivilegeScope("SERVER");
+    privilege_server.setServerName(serverName1);
+    privilege_server.setCreateTime(System.currentTimeMillis());
+
+    sentryStore.alterSentryRoleGrantPrivilege(grantor, roleName1, privilege1);
+
+    sentryStore.alterSentryRoleGrantPrivilege(grantor, roleName1, privilege1_2);
+    sentryStore.alterSentryRoleGrantPrivilege(grantor, roleName1, privilege_server);
+    sentryStore.alterSentryRoleGrantPrivilege(grantor, roleName1, privilege1_3);
+
+    // Create notification events to drop the table
+    StorageDescriptor sd = new StorageDescriptor();
+    sd.setLocation("hdfs:///db1.db/table1");
+    NotificationEvent notificationEvent = new NotificationEvent(1, 0, EventMessage.EventType.DROP_TABLE.toString(),
+        messageFactory.buildDropTableMessage(new Table(tableName1, dbName1, null, 0, 0, 0, sd, null, null, null, null, null)).toString());
+    List<NotificationEvent> events = new ArrayList<>();
+    events.add(notificationEvent);
+
+    hmsFollower.processNotifications(events);
+
+    Assert.assertEquals(1, sentryStore.getAllTSentryPrivilegesByRoleName(roleName1)
+        .size());
+  }
+
+  /**
+   * Test that SentryStore droppes the permission associated with the database when HMSFollower
+   * processes the drop database event
+   * @throws Exception
+   */
+  @Test
+  public void testDropDatabaseDropRelatedPermission() throws Exception {
+    String serverName = "server1";
+
+    // create HMSFollower
+    Configuration configuration = new Configuration();
+    configuration.set(AUTHZ_SERVER_NAME.getVar(), serverName);
+    HMSFollower hmsFollower = new HMSFollower(configuration, sentryStore, null,
+        new HiveSimpleConnectionFactory(conf, new HiveConf()), null);
+
+    // configure permission of the database
+    String roleName1 = "list-privs-r1";
+    String grantor = "g1";
+    sentryStore.createSentryRole(roleName1);
+
+    TSentryPrivilege privilege_tbl1 = new TSentryPrivilege();
+    privilege_tbl1.setPrivilegeScope("DATABASE");
+    privilege_tbl1.setServerName(serverName);
+    privilege_tbl1.setDbName(dbName1);
+    privilege_tbl1.setTableName(tableName1);
+    privilege_tbl1.setCreateTime(System.currentTimeMillis());
+
+    TSentryPrivilege privilege1 = new TSentryPrivilege(privilege_tbl1);
+    privilege1.setAction("SELECT");
+
+    TSentryPrivilege privilege1_2 = new TSentryPrivilege(privilege_tbl1);
+    privilege1_2.setAction("INSERT");
+    TSentryPrivilege privilege1_3 = new TSentryPrivilege(privilege_tbl1);
+    privilege1_3.setAction("*");
+
+    TSentryPrivilege privilege_server = new TSentryPrivilege();
+    privilege_server.setPrivilegeScope("SERVER");
+    privilege_server.setServerName(serverName1);
+    privilege_server.setCreateTime(System.currentTimeMillis());
+
+    sentryStore.alterSentryRoleGrantPrivilege(grantor, roleName1, privilege1);
+
+    sentryStore.alterSentryRoleGrantPrivilege(grantor, roleName1, privilege1_2);
+    sentryStore.alterSentryRoleGrantPrivilege(grantor, roleName1, privilege_server);
+    sentryStore.alterSentryRoleGrantPrivilege(grantor, roleName1, privilege1_3);
+
+    // Create notification events to drop the database
+    NotificationEvent notificationEvent = new NotificationEvent(1, 0, EventType.DROP_DATABASE.toString(),
+        messageFactory.buildDropDatabaseMessage(new Database(dbName1, null, "hdfs:///" + dbName1, null)).toString());
+    List<NotificationEvent> events = new ArrayList<>();
+    events.add(notificationEvent);
+
+    hmsFollower.processNotifications(events);
+
+    Assert.assertEquals(1, sentryStore.getAllTSentryPrivilegesByRoleName(roleName1)
+        .size());
+  }
+}

http://git-wip-us.apache.org/repos/asf/sentry/blob/7db84b2f/sentry-service/sentry-service-server/src/test/java/org/apache/sentry/provider/db/service/persistent/TestLeaderStatusMonitor.java
----------------------------------------------------------------------
diff --git a/sentry-service/sentry-service-server/src/test/java/org/apache/sentry/provider/db/service/persistent/TestLeaderStatusMonitor.java b/sentry-service/sentry-service-server/src/test/java/org/apache/sentry/provider/db/service/persistent/TestLeaderStatusMonitor.java
new file mode 100644
index 0000000..f6592ec
--- /dev/null
+++ b/sentry-service/sentry-service-server/src/test/java/org/apache/sentry/provider/db/service/persistent/TestLeaderStatusMonitor.java
@@ -0,0 +1,200 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * <p>
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package  org.apache.sentry.provider.db.service.persistent;
+
+import org.apache.curator.test.TestingServer;
+import org.apache.hadoop.conf.Configuration;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static java.lang.Thread.sleep;
+import static org.apache.sentry.service.common.ServiceConstants.ServerConfig.SENTRY_HA_ZOOKEEPER_QUORUM;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Unit Tests for LeaderStatusMonitor.
+ * Use Curator TestingServer as Zookeeper Server.
+ */
+@SuppressWarnings("NestedTryStatement")
+public class TestLeaderStatusMonitor {
+  private static final Logger LOGGER = LoggerFactory.getLogger(TestLeaderStatusMonitor.class);
+
+  // Delay between retries
+  private static final int DELAY_MS = 500;
+  // Maximum number of tries before giving up while waiting for leader
+  private static final int NTRIES = 360;
+  // Number of times test is repeated
+  private static final int ITERATIONS = 10;
+
+  /**
+   * Wait for some time (u to 500 seconds) until the monitor becomes active
+   * @param monitor HA monitor
+   * @return true if monitor is active, false otherwise
+   */
+  @SuppressWarnings("squid:S2925")
+  private boolean isLeader(LeaderStatusMonitor monitor) {
+    for (int i = 0; i < NTRIES; i++) {
+      if (monitor.isLeader()) {
+        return true;
+      }
+      try {
+        sleep(DELAY_MS);
+      } catch (InterruptedException ignored) {
+        Thread.interrupted();
+      }
+    }
+    return false;
+  }
+
+  /**
+   * Simple test case - leader monitor without Zookeeper.
+   * Should always be the leader.
+   * @throws Exception
+   */
+  @Test
+  public void testNoZk() throws Exception {
+    Configuration conf = new Configuration();
+    LeaderStatusMonitor monitor = new LeaderStatusMonitor(conf);
+    assertTrue(monitor.isLeader());
+  }
+
+  /**
+   * Single server scenario.
+   * Should always be the leader.
+   * Should continue to be the leader after resigning the leadership.
+   *
+   * <p>
+   * <ol>
+   * <li>Start ZK Server</li>
+   * <li>Create monitor</li>
+   * <li>Monitor should become active</li>
+   * <li>Drop active status</li>
+   * <li>Monitor should become active again</li>
+   * </ol>
+   * @throws Exception
+   */
+  @Test
+  @SuppressWarnings("squid:S2925")
+  public void testSingleServer() throws Exception {
+    try(TestingServer zkServer = new TestingServer()) {
+      zkServer.start();
+      Configuration conf = new Configuration();
+      conf.set(SENTRY_HA_ZOOKEEPER_QUORUM, zkServer.getConnectString());
+      try(LeaderStatusMonitor monitor = new LeaderStatusMonitor(conf)) {
+        monitor.init();
+        for (int i = 0; i < ITERATIONS; i++) {
+          assertTrue(isLeader(monitor));
+          LOGGER.debug("testSingleServer(): deactivating leader");
+          monitor.deactivate();
+          sleep(2 * DELAY_MS);
+          assertTrue(isLeader(monitor));
+          LOGGER.info("testSingleServer({}, leaderCount = {}", i, monitor.getLeaderCount());
+        }
+        assertEquals(ITERATIONS + 1, monitor.getLeaderCount());
+      }
+    } finally {
+      HAContext.resetHAContext();
+    }
+  }
+
+  /**
+   * Single server scenario with restarting ZK server
+   * <p>
+   * <ol>
+   * <li>Start ZK Server</li>
+   * <li>Create monitor</li>
+   * <li>at some point monitor should become active</li>
+   * <li>Restart ZK server</li>
+   * <li>at some point monitor should become active again</li>
+   * </ol>
+   * @throws Exception
+   */
+  @Test
+  public void testSingleServerZkRestart() throws Exception {
+    try(TestingServer zkServer = new TestingServer()) {
+      zkServer.start();
+      Configuration conf = new Configuration();
+      conf.set(SENTRY_HA_ZOOKEEPER_QUORUM, zkServer.getConnectString());
+      try(LeaderStatusMonitor monitor = new LeaderStatusMonitor(conf)) {
+        monitor.init();
+        for (int i = 0; i < ITERATIONS; i++) {
+          assertTrue(isLeader(monitor));
+          LOGGER.debug("testSingleServerZkRestart(): restarting Zk server");
+          zkServer.restart();
+          assertTrue(isLeader(monitor));
+          LOGGER.info("testSingleServerZkRestart({}, leaderCount = {}", i, monitor.getLeaderCount());
+          assertEquals(i + 2, monitor.getLeaderCount());
+        }
+      }
+    } finally {
+      HAContext.resetHAContext();
+    }
+  }
+
+  /**
+   * Dual server scenario
+   * <p>
+   * <ol>
+   * <li>Start ZK Server</li>
+   * <li>Create monitor1 and monitor2</li>
+   * <li>at some point one of monitors should become active</li>
+   * <li>Drop active status on monitor 2</li>
+   * <li>Monitor1 should become active</li>
+   * <li>Drop active status on monitor1</li>
+   * <li>Monitor2 should become active</li>
+   * </ol>
+   * @throws Exception
+   */
+  @Test
+  @SuppressWarnings("squid:S2925")
+  public void testTwoServers() throws Exception {
+    try(TestingServer zkServer = new TestingServer()) {
+      zkServer.start();
+      Configuration conf = new Configuration();
+      conf.set(SENTRY_HA_ZOOKEEPER_QUORUM, zkServer.getConnectString());
+      try (LeaderStatusMonitor monitor1 = new LeaderStatusMonitor(conf, "1");
+           LeaderStatusMonitor monitor2 = new LeaderStatusMonitor(conf, "2")) {
+        monitor1.init();
+        monitor2.init();
+        // Wait until one of monitors is active
+        for (int i = 0; i < NTRIES; i++) {
+          if (monitor1.isLeader() || monitor2.isLeader()) {
+            break;
+          }
+          try {
+            sleep(DELAY_MS);
+          } catch (InterruptedException ignored) {
+            Thread.interrupted();
+          }
+        }
+
+        for (int i = 0; i < ITERATIONS; i++) {
+          monitor2.deactivate();
+          assertTrue(isLeader(monitor1));
+          monitor1.deactivate();
+          assertTrue(isLeader(monitor2));
+        }
+      }
+    } finally {
+      HAContext.resetHAContext();
+    }
+  }
+}