diff --git a/src/test/java/com/uber/cadence/workflow/ManualActivityCompletionWorkflowTest.java b/src/test/java/com/uber/cadence/workflow/ManualActivityCompletionWorkflowTest.java
index 9eb15b5cf..19c32e3e8 100644
--- a/src/test/java/com/uber/cadence/workflow/ManualActivityCompletionWorkflowTest.java
+++ b/src/test/java/com/uber/cadence/workflow/ManualActivityCompletionWorkflowTest.java
@@ -17,7 +17,6 @@
 
 package com.uber.cadence.workflow;
 
-import com.google.common.base.Preconditions;
 import com.uber.cadence.WorkflowExecution;
 import com.uber.cadence.activity.Activity;
 import com.uber.cadence.activity.ActivityMethod;
@@ -48,6 +47,9 @@ public interface ManualCompletionActivities {
     @ActivityMethod
     String asyncActivity();
 
+    @ActivityMethod
+    void reset();
+
     @ActivityMethod
     void completeAsyncActivity(String result);
 
@@ -73,48 +75,61 @@ private class ManualCompletionActivitiesImpl implements ManualCompletionActiviti
     @Override
     public synchronized String asyncActivity() {
       openTask = Activity.getTask();
+      notifyAll();
 
       Activity.doNotCompleteOnReturn();
       return null;
     }
 
+    @Override
+    public synchronized void reset() {
+      openTask = null;
+    }
+
     @Override
     public synchronized void completeAsyncActivity(String details) {
-      Preconditions.checkState(openTask != null);
-      getClient().complete(openTask.getTaskToken(), details);
+      getClient().complete(getOpenTask().getTaskToken(), details);
     }
 
     @Override
     public synchronized void completeAsyncActivityById(String details) {
-      Preconditions.checkState(openTask != null);
-      getClient().complete(getCurrentWorkflow(), openTask.getActivityId(), details);
+      getClient().complete(getCurrentWorkflow(), getOpenTask().getActivityId(), details);
     }
 
     @Override
     public synchronized void failAsyncActivity(String details) {
-      Preconditions.checkState(openTask != null);
       getClient()
-          .completeExceptionally(openTask.getTaskToken(), new ExceptionWithDetaills(details));
+          .completeExceptionally(getOpenTask().getTaskToken(), new ExceptionWithDetaills(details));
     }
 
     @Override
     public synchronized void failAsyncActivityById(String details) {
-      Preconditions.checkState(openTask != null);
       getClient()
           .completeExceptionally(
-              getCurrentWorkflow(), openTask.getActivityId(), new ExceptionWithDetaills(details));
+              getCurrentWorkflow(),
+              getOpenTask().getActivityId(),
+              new ExceptionWithDetaills(details));
     }
 
     @Override
     public synchronized void cancelAsyncActivity(String details) {
-      Preconditions.checkState(openTask != null);
-      getClient().reportCancellation(openTask.getTaskToken(), details);
+      getClient().reportCancellation(getOpenTask().getTaskToken(), details);
     }
 
     @Override
     public synchronized void cancelAsyncActivityById(String details) {
-      Preconditions.checkState(openTask != null);
-      getClient().reportCancellation(getCurrentWorkflow(), openTask.getActivityId(), details);
+      getClient().reportCancellation(getCurrentWorkflow(), getOpenTask().getActivityId(), details);
+    }
+
+    private synchronized ActivityTask getOpenTask() {
+      while (openTask == null) {
+        try {
+          wait();
+        } catch (InterruptedException e) {
+          throw new RuntimeException(e);
+        }
+      }
+      return openTask;
     }
 
     private WorkflowExecution getCurrentWorkflow() {
@@ -146,21 +161,29 @@ public void run() {
       expectSuccess("1", result);
       expectFailure(() -> activities.completeAsyncActivity("again"));
 
+      activities.reset();
+
       result = Async.function(activities::asyncActivity);
       activities.completeAsyncActivityById("2");
       expectSuccess("2", result);
       expectFailure(() -> activities.completeAsyncActivityById("again"));
 
+      activities.reset();
+
       result = Async.function(activities::asyncActivity);
       activities.failAsyncActivity("3");
       expectFailureWithDetails(result, "3");
       expectFailure(() -> activities.failAsyncActivity("again"));
 
+      activities.reset();
+
       result = Async.function(activities::asyncActivity);
       activities.failAsyncActivityById("4");
       expectFailureWithDetails(result, "4");
       expectFailure(() -> activities.failAsyncActivityById("again"));
 
+      activities.reset();
+
       // Need to request  cancellation, then the activity can respond with the cancel
       CompletablePromise<String> completablePromise = Workflow.newPromise();
       CancellationScope scope =
@@ -178,6 +201,8 @@ public void run() {
       activities.cancelAsyncActivity("5");
       expectCancelled(result);
 
+      activities.reset();
+
       // Need to request  cancellation, then the activity can respond with the cancel
       CompletablePromise<String> completablePromise2 = Workflow.newPromise();
       scope =