YARN-2400. Fixed TestAMRestart fails intermittently. Contributed by Jian He

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1617029 13f79535-47bb-0310-9956-ffa450edef68

hadoop-yarn-project/CHANGES.txt

@@ -141,6 +141,8 @@ Release 2.6.0 - UNRELEASED
     YARN-2008. Fixed CapacityScheduler to calculate headroom based on max available
     capacity instead of configured max capacity. (Craig Welch via jianhe)
 
+    YARN-2400. Fixed TestAMRestart fails intermittently. (Jian He via xgong)
+
 Release 2.5.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/applicationsmanager/TestAMRestart.java

@@ -386,7 +386,8 @@ public class TestAMRestart {
     ApplicationState appState =
         memStore.getState().getApplicationState().get(app1.getApplicationId());
     // AM should be restarted even though max-am-attempt is 1.
-    MockAM am2 = MockRM.launchAndRegisterAM(app1, rm1, nm1);
+    MockAM am2 =
+        rm1.waitForNewAMToLaunchAndRegister(app1.getApplicationId(), 2, nm1);
     RMAppAttempt attempt2 = app1.getCurrentAppAttempt();
     Assert.assertTrue(((RMAppAttemptImpl) attempt2).mayBeLastAttempt());