YARN-6300. NULL_UPDATE_REQUESTS is redundant in TestFairScheduler (Contributed by Yuanbo Liu via Daniel Templeton)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestFairScheduler.java

@@ -96,7 +96,6 @@ import org.apache.hadoop.yarn.server.resourcemanager.rmnode.RMNodeResourceUpdate
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.AbstractYarnScheduler;
 
 
-import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ContainerUpdates;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.QueueMetrics;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerApplicationAttempt;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerNode;
@@ -119,7 +118,6 @@ import org.junit.After;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
-import org.mockito.Mock;
 import org.mockito.Mockito;
 import org.xml.sax.SAXException;
 
@@ -130,8 +128,6 @@ public class TestFairScheduler extends FairSchedulerTestBase {
   private final int GB = 1024;
   private final static String ALLOC_FILE =
       new File(TEST_DIR, "test-queues").getAbsolutePath();
-  private final static ContainerUpdates NULL_UPDATE_REQUESTS =
-      new ContainerUpdates();
 
   @Before
   public void setUp() throws IOException {