Add unit tests for HandlerThreadScheduler

Author: mttkay

rxjava-contrib/rxjava-android/src/main/java/rx/concurrency/HandlerThreadScheduler.java

@@ -1,13 +1,24 @@
 package rx.concurrency;
 
 import android.os.Handler;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
 import rx.Scheduler;
 import rx.Subscription;
+import rx.android.testsupport.AndroidTestRunner;
 import rx.operators.AtomicObservableSubscription;
 import rx.util.functions.Func2;
 
 import java.util.concurrent.TimeUnit;
 
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.anyLong;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+
 /**
  * Schedules actions to run on an Android Handler thread.
  */
@@ -49,6 +60,61 @@ public void run() {
             return subscription;
         }
     }
+
+    @RunWith(AndroidTestRunner.class)
+    public static final class UnitTest {
+
+        @Test
+        public void shouldScheduleActionOnHandlerThread() {
+            final Handler handler = mock(Handler.class);
+            final Object state = new Object();
+            final Func2<Scheduler, Object, Subscription> action = mock(Func2.class);
+
+            Scheduler scheduler = new HandlerThreadScheduler(handler);
+            scheduler.schedule(state, action);
+
+            // verify that we post to the given Handler
+            ArgumentCaptor<Runnable> runnable = ArgumentCaptor.forClass(Runnable.class);
+            verify(handler).post(runnable.capture());
+
+            // verify that the given handler delegates to our action
+            runnable.getValue().run();
+            verify(action).call(scheduler, state);
+        }
+
+        @Test
+        public void shouldScheduleDelayedActionOnHandlerThread() {
+            final Handler handler = mock(Handler.class);
+            final Object state = new Object();
+            final Func2<Scheduler, Object, Subscription> action = mock(Func2.class);
+
+            Scheduler scheduler = new HandlerThreadScheduler(handler);
+            scheduler.schedule(state, action, 1L, TimeUnit.SECONDS);
+
+            // verify that we post to the given Handler
+            ArgumentCaptor<Runnable> runnable = ArgumentCaptor.forClass(Runnable.class);
+            verify(handler).postDelayed(runnable.capture(), eq(1000L));
+
+            // verify that the given handler delegates to our action
+            runnable.getValue().run();
+            verify(action).call(scheduler, state);
+        }
+
+        @Test
+        public void scheduleDelayedActionShouldForwardToNormalPostIfDelayIsZero() {
+            final Handler handler = mock(Handler.class);
+            final Object state = new Object();
+            final Func2<Scheduler, Object, Subscription> action = mock(Func2.class);
+
+            Scheduler scheduler = new HandlerThreadScheduler(handler);
+            scheduler.schedule(state, action, 0L, TimeUnit.SECONDS);
+
+            // verify that we post to the given Handler
+            verify(handler).post(any(Runnable.class));
+            verify(handler, never()).postDelayed(any(Runnable.class), anyLong());
+        }
+
+    }
 }