diff --git a/indexing-service/src/test/java/io/druid/indexing/overlord/RemoteTaskRunnerRunPendingTasksConcurrencyTest.java b/indexing-service/src/test/java/io/druid/indexing/overlord/RemoteTaskRunnerRunPendingTasksConcurrencyTest.java
index 6f77215834a..66cd9e73288 100644
--- a/indexing-service/src/test/java/io/druid/indexing/overlord/RemoteTaskRunnerRunPendingTasksConcurrencyTest.java
+++ b/indexing-service/src/test/java/io/druid/indexing/overlord/RemoteTaskRunnerRunPendingTasksConcurrencyTest.java
@@ -23,9 +23,11 @@
 package io.druid.indexing.overlord;
 
 import com.google.common.util.concurrent.ListenableFuture;
+import com.metamx.common.ISE;
 import io.druid.indexing.common.TaskStatus;
 import io.druid.indexing.common.TestTasks;
 import io.druid.indexing.common.task.Task;
+import org.apache.zookeeper.ZooKeeper;
 import org.joda.time.Period;
 import org.junit.After;
 import org.junit.Assert;
@@ -81,9 +83,7 @@ public class RemoteTaskRunnerRunPendingTasksConcurrencyTest
       results[i] = (remoteTaskRunner.run(tasks[i]));
     }
 
-    while (remoteTaskRunner.getWorkersWithUnacknowledgedTask().size() < 2) {
-      Thread.sleep(5);
-    }
+    waitForBothWorkersToHaveUnackedTasks();
 
     //3 more tasks, all of which get queued up
     for (int i = 2; i < 5; i++) {
@@ -92,52 +92,40 @@ public class RemoteTaskRunnerRunPendingTasksConcurrencyTest
     }
 
     //simulate completion of task0 and task1
-    if (rtrTestUtils.taskAnnounced("worker0", tasks[0].getId())) {
-      rtrTestUtils.mockWorkerRunningTask("worker0", tasks[0]);
-      rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker0", tasks[0]);
-      rtrTestUtils.mockWorkerRunningTask("worker1", tasks[1]);
-      rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker1", tasks[1]);
-    } else {
-      rtrTestUtils.mockWorkerRunningTask("worker0", tasks[1]);
-      rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker0", tasks[1]);
-      rtrTestUtils.mockWorkerRunningTask("worker1", tasks[0]);
-      rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker1", tasks[0]);
-    }
+    mockWorkerRunningAndCompletionSuccessfulTasks(tasks[0], tasks[1]);
 
     Assert.assertEquals(TaskStatus.Status.SUCCESS, results[0].get().getStatusCode());
     Assert.assertEquals(TaskStatus.Status.SUCCESS, results[1].get().getStatusCode());
 
     // now both threads race to run the last 3 tasks. task2 and task3 are being assigned
-    while (remoteTaskRunner.getWorkersWithUnacknowledgedTask().size() < 2) {
-      Thread.sleep(5);
-    }
+    waitForBothWorkersToHaveUnackedTasks();
 
-    //cancel task4, both executor threads should be able to ignore task4
-    remoteTaskRunner.shutdown("task4");
-
-    //simulate completion of task3 before task2 so that the executor thread with task2
-    //gets to task3 and ignores it
-    if (rtrTestUtils.taskAnnounced("worker0", tasks[3].getId())) {
-      rtrTestUtils.mockWorkerRunningTask("worker0", tasks[3]);
-      rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker0", tasks[3]);
-      rtrTestUtils.mockWorkerRunningTask("worker1", tasks[2]);
-      rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker1", tasks[2]);
+    if (remoteTaskRunner.getWorkersWithUnacknowledgedTask().containsValue(tasks[2].getId())
+        && remoteTaskRunner.getWorkersWithUnacknowledgedTask().containsValue(tasks[3].getId())) {
+      remoteTaskRunner.shutdown("task4");
+      mockWorkerRunningAndCompletionSuccessfulTasks(tasks[3], tasks[2]);
+      Assert.assertEquals(TaskStatus.Status.SUCCESS, results[3].get().getStatusCode());
+      Assert.assertEquals(TaskStatus.Status.SUCCESS, results[2].get().getStatusCode());
+    } else if (remoteTaskRunner.getWorkersWithUnacknowledgedTask().containsValue(tasks[3].getId())
+               && remoteTaskRunner.getWorkersWithUnacknowledgedTask().containsValue(tasks[4].getId())) {
+      remoteTaskRunner.shutdown("task2");
+      mockWorkerRunningAndCompletionSuccessfulTasks(tasks[4], tasks[3]);
+      Assert.assertEquals(TaskStatus.Status.SUCCESS, results[4].get().getStatusCode());
+      Assert.assertEquals(TaskStatus.Status.SUCCESS, results[3].get().getStatusCode());
+    } else if (remoteTaskRunner.getWorkersWithUnacknowledgedTask().containsValue(tasks[4].getId())
+               && remoteTaskRunner.getWorkersWithUnacknowledgedTask().containsValue(tasks[2].getId())) {
+      remoteTaskRunner.shutdown("task3");
+      mockWorkerRunningAndCompletionSuccessfulTasks(tasks[4], tasks[2]);
+      Assert.assertEquals(TaskStatus.Status.SUCCESS, results[4].get().getStatusCode());
+      Assert.assertEquals(TaskStatus.Status.SUCCESS, results[2].get().getStatusCode());
     } else {
-      rtrTestUtils.mockWorkerRunningTask("worker1", tasks[3]);
-      rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker1", tasks[3]);
-      rtrTestUtils.mockWorkerRunningTask("worker0", tasks[2]);
-      rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker0", tasks[2]);
+      throw new ISE("two out of three tasks 2,3 and 4 must be waiting for ack.");
     }
 
-    Assert.assertEquals(TaskStatus.Status.SUCCESS, results[2].get().getStatusCode());
-    Assert.assertEquals(TaskStatus.Status.SUCCESS, results[3].get().getStatusCode());
-
     //ensure that RTR is doing OK and still making progress
     tasks[5] = TestTasks.unending("task5");
     results[5] = remoteTaskRunner.run(tasks[5]);
-    while (remoteTaskRunner.getWorkersWithUnacknowledgedTask().size() < 1) {
-      Thread.sleep(5);
-    }
+    waitForOneWorkerToHaveUnackedTasks();
     if (rtrTestUtils.taskAnnounced("worker0", tasks[5].getId())) {
       rtrTestUtils.mockWorkerRunningTask("worker0", tasks[5]);
       rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker0", tasks[5]);
@@ -147,4 +135,45 @@ public class RemoteTaskRunnerRunPendingTasksConcurrencyTest
     }
     Assert.assertEquals(TaskStatus.Status.SUCCESS, results[5].get().getStatusCode());
   }
+
+  private void mockWorkerRunningAndCompletionSuccessfulTasks(Task t1, Task t2) throws Exception
+  {
+    if (rtrTestUtils.taskAnnounced("worker0", t1.getId())) {
+      rtrTestUtils.mockWorkerRunningTask("worker0", t1);
+      rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker0", t1);
+      rtrTestUtils.mockWorkerRunningTask("worker1", t2);
+      rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker1", t2);
+    } else {
+      rtrTestUtils.mockWorkerRunningTask("worker1", t1);
+      rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker1", t1);
+      rtrTestUtils.mockWorkerRunningTask("worker0", t2);
+      rtrTestUtils.mockWorkerCompleteSuccessfulTask("worker0", t2);
+    }
+  }
+
+  private void waitForOneWorkerToHaveUnackedTasks() throws Exception
+  {
+    while (remoteTaskRunner.getWorkersWithUnacknowledgedTask().size() < 1) {
+      Thread.sleep(5);
+    }
+
+    ZooKeeper zk = rtrTestUtils.getCuratorFramework().getZookeeperClient().getZooKeeper();
+    while (zk.getChildren(rtrTestUtils.tasksPath + "/worker0", false).size() < 1
+           && zk.getChildren(rtrTestUtils.tasksPath + "/worker1", false).size() < 1) {
+      Thread.sleep(5);
+    }
+  }
+
+  private void waitForBothWorkersToHaveUnackedTasks() throws Exception
+  {
+    while (remoteTaskRunner.getWorkersWithUnacknowledgedTask().size() < 2) {
+      Thread.sleep(5);
+    }
+
+    ZooKeeper zk = rtrTestUtils.getCuratorFramework().getZookeeperClient().getZooKeeper();
+    while (zk.getChildren(rtrTestUtils.tasksPath + "/worker0", false).size() < 1
+           || zk.getChildren(rtrTestUtils.tasksPath + "/worker1", false).size() < 1) {
+      Thread.sleep(5);
+    }
+  }
 }