diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/TestOpportunisticContainerAllocatorAMService.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/TestOpportunisticContainerAllocatorAMService.java
index 1af930f7fc..efa76bcf92 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/TestOpportunisticContainerAllocatorAMService.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/TestOpportunisticContainerAllocatorAMService.java
@@ -243,13 +243,13 @@ public void testContainerPromoteAndDemoteBeforeContainerStart() throws Exception
             null, ExecutionType.GUARANTEED)));
     // Node on same host should not result in allocation
     sameHostDiffNode.nodeHeartbeat(true);
-    Thread.sleep(200);
+    rm.drainEvents();
     allocateResponse =  am1.allocate(new ArrayList<>(), new ArrayList<>());
     Assert.assertEquals(0, allocateResponse.getUpdatedContainers().size());
 
     // Wait for scheduler to process all events
     dispatcher.waitForEventThreadToWait();
-    Thread.sleep(1000);
+    rm.drainEvents();
     // Verify Metrics After OPP allocation (Nothing should change again)
     verifyMetrics(metrics, 15360, 15, 1024, 1, 1);
 
@@ -286,7 +286,7 @@ public void testContainerPromoteAndDemoteBeforeContainerStart() throws Exception
 
     // Ensure after correct node heartbeats, we should get the allocation
     allocNode.nodeHeartbeat(true);
-    Thread.sleep(200);
+    rm.drainEvents();
     allocateResponse =  am1.allocate(new ArrayList<>(), new ArrayList<>());
     Assert.assertEquals(1, allocateResponse.getUpdatedContainers().size());
     Container uc =
@@ -303,7 +303,7 @@ public void testContainerPromoteAndDemoteBeforeContainerStart() throws Exception
     nm2.nodeHeartbeat(true);
     nm3.nodeHeartbeat(true);
     nm4.nodeHeartbeat(true);
-    Thread.sleep(200);
+    rm.drainEvents();
 
     // Verify that the container is still in ACQUIRED state wrt the RM.
     RMContainer rmContainer = ((CapacityScheduler) scheduler)
@@ -325,6 +325,7 @@ public void testContainerPromoteAndDemoteBeforeContainerStart() throws Exception
 
     // Wait for scheduler to finish processing events
     dispatcher.waitForEventThreadToWait();
+    rm.drainEvents();
     // Verify Metrics After OPP allocation :
     // Everything should have reverted to what it was
     verifyMetrics(metrics, 15360, 15, 1024, 1, 1);
@@ -396,7 +397,7 @@ public void testContainerPromoteAfterContainerStart() throws Exception {
         ContainerStatus.newInstance(container.getId(),
             ExecutionType.OPPORTUNISTIC, ContainerState.RUNNING, "", 0)),
         true);
-    Thread.sleep(200);
+    rm.drainEvents();
 
     // Verify that container is actually running wrt the RM..
     RMContainer rmContainer = ((CapacityScheduler) scheduler)
@@ -434,7 +435,7 @@ public void testContainerPromoteAfterContainerStart() throws Exception {
         ContainerStatus.newInstance(container.getId(),
             ExecutionType.OPPORTUNISTIC, ContainerState.RUNNING, "", 0)),
         true);
-    Thread.sleep(200);
+    rm.drainEvents();
 
     allocateResponse =  am1.allocate(new ArrayList<>(), new ArrayList<>());
     Assert.assertEquals(1, allocateResponse.getUpdatedContainers().size());
@@ -521,7 +522,7 @@ public void testContainerPromoteAfterContainerComplete() throws Exception {
         ContainerStatus.newInstance(container.getId(),
             ExecutionType.OPPORTUNISTIC, ContainerState.RUNNING, "", 0)),
         true);
-    Thread.sleep(200);
+    rm.drainEvents();
 
     // Verify that container is actually running wrt the RM..
     RMContainer rmContainer = ((CapacityScheduler) scheduler)
@@ -535,7 +536,7 @@ public void testContainerPromoteAfterContainerComplete() throws Exception {
         ContainerStatus.newInstance(container.getId(),
             ExecutionType.OPPORTUNISTIC, ContainerState.COMPLETE, "", 0)),
         true);
-    Thread.sleep(200);
+    rm.drainEvents();
 
     // Verify that container has been removed..
     rmContainer = ((CapacityScheduler) scheduler)
@@ -618,7 +619,7 @@ public void testContainerAutoUpdateContainer() throws Exception {
     nm1.nodeHeartbeat(Arrays.asList(ContainerStatus
         .newInstance(container.getId(), ExecutionType.OPPORTUNISTIC,
             ContainerState.RUNNING, "", 0)), true);
-    Thread.sleep(200);
+    rm.drainEvents();
 
     // Verify that container is actually running wrt the RM..
     RMContainer rmContainer = ((CapacityScheduler) scheduler)
@@ -636,7 +637,7 @@ public void testContainerAutoUpdateContainer() throws Exception {
     nm1.nodeHeartbeat(Arrays.asList(ContainerStatus
         .newInstance(container.getId(), ExecutionType.OPPORTUNISTIC,
             ContainerState.RUNNING, "", 0)), true);
-    Thread.sleep(200);
+    rm.drainEvents();
     // Get the update response on next allocate
     allocateResponse = am1.allocate(new ArrayList<>(), new ArrayList<>());
     // Check the update response from YARNRM
@@ -662,7 +663,7 @@ public void testContainerAutoUpdateContainer() throws Exception {
         .newInstance(container.getId(), ExecutionType.GUARANTEED,
             ContainerState.RUNNING, "", 0)), true);
 
-    Thread.sleep(200);
+    rm.drainEvents();
     if (allocateResponse.getUpdatedContainers().size() == 0) {
       allocateResponse = am1.allocate(new ArrayList<>(), new ArrayList<>());
     }
@@ -671,7 +672,7 @@ public void testContainerAutoUpdateContainer() throws Exception {
     Assert.assertEquals(container.getId(), uc.getContainer().getId());
     Assert.assertEquals(Resource.newInstance(2 * GB, 1),
         uc.getContainer().getResource());
-    Thread.sleep(1000);
+    rm.drainEvents();
 
     // Check that the container resources are increased in
     // NM through NM heartbeat response
@@ -688,7 +689,7 @@ public void testContainerAutoUpdateContainer() throws Exception {
             ContainerUpdateType.DECREASE_RESOURCE,
             Resources.createResource(1 * GB, 1), null)));
     Assert.assertEquals(1, allocateResponse.getUpdatedContainers().size());
-    Thread.sleep(1000);
+    rm.drainEvents();
 
     // Check that the container resources are decreased
     // in NM through NM heartbeat response
@@ -707,7 +708,7 @@ public void testContainerAutoUpdateContainer() throws Exception {
     response = nm1.nodeHeartbeat(Arrays.asList(ContainerStatus
         .newInstance(container.getId(), ExecutionType.GUARANTEED,
             ContainerState.RUNNING, "", 0)), true);
-    Thread.sleep(200);
+    rm.drainEvents();
     if (allocateResponse.getUpdatedContainers().size() == 0) {
       // Get the update response on next allocate
       allocateResponse = am1.allocate(new ArrayList<>(), new ArrayList<>());