Fix the bug that Switch doesn't propagate 'unsubscribe'

Author: zsxwing

src/main/java/rx/internal/operators/OperatorSwitch.java

@@ -62,6 +62,7 @@ private static final class SwitchSubscriber<T> extends Subscriber<Observable<? e
         volatile boolean infinite = false;
 
         public SwitchSubscriber(Subscriber<? super T> child) {
+            super(child);
             s = new SerializedSubscriber<T>(child);
             ssub = new SerialSubscription();
             child.add(ssub);

src/test/java/rx/internal/operators/OperatorSwitchTest.java

@@ -15,6 +15,7 @@
  */
 package rx.internal.operators;
 
+import static org.junit.Assert.assertTrue;
 import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.anyString;
 import static org.mockito.Mockito.inOrder;
@@ -25,6 +26,7 @@
 
 import java.util.Arrays;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -513,4 +515,19 @@ public void onNext(String s) {
         testSubscriber.assertNoErrors();
         testSubscriber.assertTerminalEvent();
     }
+
+    @Test
+    public void testUnsubscribe() {
+        final AtomicBoolean isUnsubscribed = new AtomicBoolean();
+        Observable.switchOnNext(
+                Observable.create(new Observable.OnSubscribe<Observable<Integer>>() {
+                    @Override
+                    public void call(final Subscriber<? super Observable<Integer>> subscriber) {
+                        subscriber.onNext(Observable.just(1));
+                        isUnsubscribed.set(subscriber.isUnsubscribed());
+                    }
+                })
+        ).take(1).subscribe();
+        assertTrue("Switch doesn't propagate 'unsubscribe'", isUnsubscribed.get());
+    }
 }