MAPREDUCE-4784. TestRecovery occasionally fails. Contributed by Haibo Chen

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

@@ -35,6 +35,7 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 
+import java.util.concurrent.TimeoutException;
 import org.junit.Assert;
 
 import org.apache.commons.logging.Log;
@@ -180,7 +181,10 @@ public class TestRecovery {
     Iterator<TaskAttempt> itr = mapTask1.getAttempts().values().iterator();
     itr.next();
     TaskAttempt task1Attempt2 = itr.next();
-    
+
+    // wait for the second task attempt to be assigned.
+    waitForContainerAssignment(task1Attempt2);
+
     // This attempt will automatically fail because of the way ContainerLauncher
     // is setup
     // This attempt 'disappears' from JobHistory and so causes MAPREDUCE-3846
@@ -317,6 +321,21 @@ public class TestRecovery {
     // available in the failed attempt should be available here
   }
 
+  /**
+   * Wait for a task attempt to be assigned a container to.
+   * @param task1Attempt2 the task attempt to wait for its container assignment
+   * @throws TimeoutException if times out
+   * @throws InterruptedException if interrupted
+   */
+  public static void waitForContainerAssignment(final TaskAttempt task1Attempt2)
+      throws TimeoutException, InterruptedException {
+    GenericTestUtils.waitFor(new Supplier<Boolean>() {
+      @Override public Boolean get() {
+        return task1Attempt2.getAssignedContainerID() != null;
+      }
+    }, 10, 10000);
+  }
+
   /**
    * AM with 3 maps and 0 reduce. AM crashes after the first two tasks finishes
    * and recovers completely and succeeds in the second generation.
@@ -1199,11 +1218,7 @@ public class TestRecovery {
     TaskAttempt task2Attempt = mapTask2.getAttempts().values().iterator().next();
 
     // wait for the second task attempt to be assigned.
-    GenericTestUtils.waitFor(new Supplier<Boolean>() {
-      @Override public Boolean get() {
-        return task1Attempt2.getAssignedContainerID() != null;
-      }
-    }, 10, 10000);
+    waitForContainerAssignment(task1Attempt2);
     ContainerId t1a2contId = task1Attempt2.getAssignedContainerID();
 
     LOG.info(t1a2contId.toString());