Merge pull request #347 from samueltardieu/issue-346

Schedule tasks with negative delays immediately as per Scheduler spec

Author: JakeWharton

rxandroid/src/main/java/io/reactivex/android/schedulers/HandlerScheduler.java

@@ -31,12 +31,11 @@ final class HandlerScheduler extends Scheduler {
     @Override
     public Disposable scheduleDirect(Runnable run, long delay, TimeUnit unit) {
         if (run == null) throw new NullPointerException("run == null");
-        if (delay < 0) throw new IllegalArgumentException("delay < 0: " + delay);
         if (unit == null) throw new NullPointerException("unit == null");
 
         run = RxJavaPlugins.onSchedule(run);
         ScheduledRunnable scheduled = new ScheduledRunnable(handler, run);
-        handler.postDelayed(scheduled, unit.toMillis(delay));
+        handler.postDelayed(scheduled, Math.max(0L, unit.toMillis(delay)));
         return scheduled;
     }
 
@@ -57,7 +56,6 @@ private static final class HandlerWorker extends Worker {
         @Override
         public Disposable schedule(Runnable run, long delay, TimeUnit unit) {
             if (run == null) throw new NullPointerException("run == null");
-            if (delay < 0) throw new IllegalArgumentException("delay < 0: " + delay);
             if (unit == null) throw new NullPointerException("unit == null");
 
             if (disposed) {
@@ -71,7 +69,7 @@ public Disposable schedule(Runnable run, long delay, TimeUnit unit) {
             Message message = Message.obtain(handler, scheduled);
             message.obj = this; // Used as token for batch disposal of this worker's runnables.
 
-            handler.sendMessageDelayed(message, unit.toMillis(delay));
+            handler.sendMessageDelayed(message, Math.max(0L, unit.toMillis(delay)));
 
             // Re-check disposed state for removing in case we were racing a call to dispose().
             if (disposed) {

rxandroid/src/test/java/io/reactivex/android/schedulers/HandlerSchedulerTest.java

@@ -72,6 +72,15 @@ public void directScheduleOncePostsImmediately() {
         assertEquals(1, counter.get());
     }
 
+    @Test
+    public void directScheduleOnceWithNegativeDelayPostsImmediately() {
+        CountingRunnable counter = new CountingRunnable();
+        scheduler.scheduleDirect(counter, -1, TimeUnit.MINUTES);
+
+        runUiThreadTasks();
+        assertEquals(1, counter.get());
+    }
+
     @Test
     public void directScheduleOnceUsesHook() {
         final CountingRunnable newCounter = new CountingRunnable();
@@ -300,6 +309,17 @@ public void workerScheduleOncePostsImmediately() {
         assertEquals(1, counter.get());
     }
 
+    @Test
+    public void workerScheduleOnceWithNegativeDelayPostsImmediately() {
+        Worker worker = scheduler.createWorker();
+
+        CountingRunnable counter = new CountingRunnable();
+        worker.schedule(counter, -1, TimeUnit.MINUTES);
+
+        runUiThreadTasks();
+        assertEquals(1, counter.get());
+    }
+
     @Test
     public void workerScheduleOnceUsesHook() {
         final CountingRunnable newCounter = new CountingRunnable();
@@ -665,12 +685,6 @@ public void directScheduleOnceInputValidation() {
         } catch (NullPointerException e) {
             assertEquals("run == null", e.getMessage());
         }
-        try {
-            scheduler.scheduleDirect(new CountingRunnable(), -1, MINUTES);
-            fail();
-        } catch (IllegalArgumentException e) {
-            assertEquals("delay < 0: -1", e.getMessage());
-        }
         try {
             scheduler.scheduleDirect(new CountingRunnable(), 1, null);
             fail();
@@ -687,12 +701,6 @@ public void directSchedulePeriodicallyInputValidation() {
         } catch (NullPointerException e) {
             assertEquals("run == null", e.getMessage());
         }
-        try {
-            scheduler.schedulePeriodicallyDirect(new CountingRunnable(), -1, 1, MINUTES);
-            fail();
-        } catch (IllegalArgumentException e) {
-            assertEquals("delay < 0: -1", e.getMessage());
-        }
         try {
             scheduler.schedulePeriodicallyDirect(new CountingRunnable(), 1, -1, MINUTES);
             fail();
@@ -722,12 +730,6 @@ public void workerScheduleOnceInputValidation() {
         } catch (NullPointerException e) {
             assertEquals("run == null", e.getMessage());
         }
-        try {
-            worker.schedule(new CountingRunnable(), -1, MINUTES);
-            fail();
-        } catch (IllegalArgumentException e) {
-            assertEquals("delay < 0: -1", e.getMessage());
-        }
         try {
             worker.schedule(new CountingRunnable(), 1, null);
             fail();
@@ -745,12 +747,6 @@ public void workerSchedulePeriodicallyInputValidation() {
         } catch (NullPointerException e) {
             assertEquals("run == null", e.getMessage());
         }
-        try {
-            worker.schedulePeriodically(new CountingRunnable(), -1, 1, MINUTES);
-            fail();
-        } catch (IllegalArgumentException e) {
-            assertEquals("delay < 0: -1", e.getMessage());
-        }
         try {
             worker.schedulePeriodically(new CountingRunnable(), 1, -1, MINUTES);
             fail();