MAPREDUCE-6898. TestKill.testKillTask is flaky. Contributed by Peter Bacsko

(cherry picked from commit e78542f4bea90e8545e9e06af9c07e89d2be43d9)

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/TestKill.java

@@ -21,11 +21,15 @@ package org.apache.hadoop.mapreduce.v2.app;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
 
 import org.apache.hadoop.service.Service;
 import org.junit.Assert;
-
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.mapreduce.jobhistory.EventType;
+import org.apache.hadoop.mapreduce.jobhistory.TaskStartedEvent;
 import org.apache.hadoop.mapreduce.v2.api.records.JobId;
 import org.apache.hadoop.mapreduce.v2.api.records.JobState;
 import org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId;
@@ -100,12 +104,34 @@ public class TestKill {
   @Test
   public void testKillTask() throws Exception {
     final CountDownLatch latch = new CountDownLatch(1);
-    MRApp app = new BlockingMRApp(2, 0, latch);
+    final CountDownLatch jobRunning = new CountDownLatch(1);
+
+    final Dispatcher dispatcher = new AsyncDispatcher() {
+      protected void dispatch(Event event) {
+        // We have to wait until the internal state is RUNNING and not SETUP
+        // because it can cause a transition failure. If the dispatchable
+        // event is TASK_STARTED, we can continue because the job must be in
+        // RUNNING at that point.
+        if (event.getType() == EventType.TASK_STARTED) {
+          jobRunning.countDown();
+        }
+        super.dispatch(event);
+      }
+    };
+
+    MRApp app = new BlockingMRApp(2, 0, latch) {
+      @Override
+      public Dispatcher createDispatcher() {
+        return dispatcher;
+      }
+    };
+
     //this will start the job but job won't complete as Task is blocked
     Job job = app.submit(new Configuration());
-    
-    //wait and vailidate for Job to become RUNNING
-    app.waitForInternalState((JobImpl) job, JobStateInternal.RUNNING);
+
+    // wait until the job transitions to JobInternalState.RUNNING
+    jobRunning.await(10, TimeUnit.SECONDS);
+
     Map<TaskId,Task> tasks = job.getTasks();
     Assert.assertEquals("No of tasks is not correct", 2, 
         tasks.size());