1.x: Fix SyncOnSubscribeTest.testConcurrentRequests non-determinism

The test checks if onUnSubscribe is called but that happens after
onCompleted is sent and as such, may run concurrently with the main
thread where the mock is verified. The change switches to CountDownLatch
to properly await the call to onUnsubscribe.

Author: akarnokd

src/test/java/rx/observables/SyncOnSubscribeTest.java

@@ -476,8 +476,14 @@ public void testConcurrentRequests() throws InterruptedException {
         final CountDownLatch l1 = new CountDownLatch(1);
         final CountDownLatch l2 = new CountDownLatch(1);
 
-        @SuppressWarnings("unchecked")
-        Action1<? super Integer> onUnSubscribe = mock(Action1.class);
+        final CountDownLatch l3 = new CountDownLatch(1);
+
+        final Action1<Object> onUnSubscribe = new Action1<Object>() {
+            @Override
+            public void call(Object t) {
+                l3.countDown();
+            }
+        };
 
         OnSubscribe<Integer> os = SyncOnSubscribe.createStateful(
                 new Func0<Integer>() {
@@ -532,7 +538,10 @@ public Integer call(Integer state, Observer<? super Integer> observer) {
         inOrder.verify(o, times(finalCount)).onNext(any());
         inOrder.verify(o, times(1)).onCompleted();
         inOrder.verifyNoMoreInteractions();
-        verify(onUnSubscribe, times(1)).call(any(Integer.class));
+        
+        if (!l3.await(2, TimeUnit.SECONDS)) {
+            fail("SyncOnSubscribe failed to countDown onUnSubscribe latch");
+        }
     }
 
     @Test