Test setPlaybackParameters before preparation completes

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=176837939

library/core/src/androidTest/java/com/google/android/exoplayer2/ExoPlayerTest.java

@@ -570,4 +570,48 @@ public final class ExoPlayerTest extends TestCase {
     testRunner.assertPlayedPeriodIndices(0, 1, 0);
   }
 
+  public void testSetPlaybackParametersBeforePreparationCompletesSucceeds() throws Exception {
+    // Test that no exception is thrown when playback parameters are updated between creating a
+    // period and preparation of the period completing.
+    final CountDownLatch createPeriodCalledCountDownLatch = new CountDownLatch(1);
+    final FakeMediaPeriod[] fakeMediaPeriodHolder = new FakeMediaPeriod[1];
+    MediaSource mediaSource =
+        new FakeMediaSource(new FakeTimeline(/* windowCount= */ 1), null, Builder.VIDEO_FORMAT) {
+          @Override
+          protected FakeMediaPeriod createFakeMediaPeriod(
+              MediaPeriodId id, TrackGroupArray trackGroupArray, Allocator allocator) {
+            // Defer completing preparation of the period until playback parameters have been set.
+            fakeMediaPeriodHolder[0] =
+                new FakeMediaPeriod(trackGroupArray, /* deferOnPrepared= */ true);
+            createPeriodCalledCountDownLatch.countDown();
+            return fakeMediaPeriodHolder[0];
+          }
+        };
+    ActionSchedule actionSchedule =
+        new ActionSchedule.Builder("testSetPlaybackParametersBeforePreparationCompletesSucceeds")
+            .waitForPlaybackState(Player.STATE_BUFFERING)
+            // Block until createPeriod has been called on the fake media source.
+            .executeRunnable(new Runnable() {
+              @Override
+              public void run() {
+                try {
+                  createPeriodCalledCountDownLatch.await();
+                } catch (InterruptedException e) {
+                  throw new IllegalStateException(e);
+                }
+              }
+            })
+            // Set playback parameters (while the fake media period is not yet prepared).
+            .setPlaybackParameters(new PlaybackParameters(2f, 2f))
+            // Complete preparation of the fake media period.
+            .executeRunnable(new Runnable() {
+              @Override
+              public void run() {
+                fakeMediaPeriodHolder[0].setPreparationComplete();
+              }
+            })
+            .build();
+    new ExoPlayerTestRunner.Builder().setMediaSource(mediaSource).setActionSchedule(actionSchedule)
+        .build().start().blockUntilEnded(TIMEOUT_MS);
+  }
 }

testutils/src/main/java/com/google/android/exoplayer2/testutil/Action.java

@@ -19,6 +19,7 @@ import android.os.Handler;
 import android.util.Log;
 import android.view.Surface;
 import com.google.android.exoplayer2.ExoPlayer;
+import com.google.android.exoplayer2.PlaybackParameters;
 import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.SimpleExoPlayer;
 import com.google.android.exoplayer2.Timeline;
@@ -304,6 +305,30 @@ public abstract class Action {
   }
 
   /**
+   * Calls {@link Player#setPlaybackParameters(PlaybackParameters)}.
+   */
+  public static final class SetPlaybackParameters extends Action {
+
+    private final PlaybackParameters playbackParameters;
+
+    /**
+     * @param tag A tag to use for logging.
+     * @param playbackParameters The playback parameters.
+     */
+    public SetPlaybackParameters(String tag, PlaybackParameters playbackParameters) {
+      super(tag, "SetPlaybackParameters:" + playbackParameters);
+      this.playbackParameters = playbackParameters;
+    }
+
+    @Override
+    protected void doActionImpl(SimpleExoPlayer player, MappingTrackSelector trackSelector,
+        Surface surface) {
+      player.setPlaybackParameters(playbackParameters);
+    }
+
+  }
+
+  /**
    * Waits for {@link Player.EventListener#onTimelineChanged(Timeline, Object, int)}.
    */
   public static final class WaitForTimelineChanged extends Action {

testutils/src/main/java/com/google/android/exoplayer2/testutil/ActionSchedule.java

@@ -19,6 +19,7 @@ import android.os.Handler;
 import android.os.Looper;
 import android.view.Surface;
 import com.google.android.exoplayer2.C;
+import com.google.android.exoplayer2.PlaybackParameters;
 import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.SimpleExoPlayer;
 import com.google.android.exoplayer2.Timeline;
@@ -28,6 +29,7 @@ import com.google.android.exoplayer2.testutil.Action.ExecuteRunnable;
 import com.google.android.exoplayer2.testutil.Action.PrepareSource;
 import com.google.android.exoplayer2.testutil.Action.Seek;
 import com.google.android.exoplayer2.testutil.Action.SetPlayWhenReady;
+import com.google.android.exoplayer2.testutil.Action.SetPlaybackParameters;
 import com.google.android.exoplayer2.testutil.Action.SetRendererDisabled;
 import com.google.android.exoplayer2.testutil.Action.SetRepeatMode;
 import com.google.android.exoplayer2.testutil.Action.SetShuffleModeEnabled;
@@ -152,6 +154,17 @@ public final class ActionSchedule {
     }
 
     /**
+     * Schedules a playback parameters setting action to be executed.
+     *
+     * @param playbackParameters The playback parameters to set.
+     * @return The builder, for convenience.
+     * @see Player#setPlaybackParameters(PlaybackParameters)
+     */
+    public Builder setPlaybackParameters(PlaybackParameters playbackParameters) {
+      return apply(new SetPlaybackParameters(tag, playbackParameters));
+    }
+
+    /**
      * Schedules a stop action to be executed.
      *
      * @return The builder, for convenience.

testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeMediaPeriod.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.testutil;
 
+import android.os.Handler;
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.source.MediaPeriod;
 import com.google.android.exoplayer2.source.SampleStream;
@@ -32,12 +34,30 @@ public class FakeMediaPeriod implements MediaPeriod {
 
   private final TrackGroupArray trackGroupArray;
 
-  private boolean preparedPeriod;
+  @Nullable private Handler playerHandler;
+  @Nullable private Callback prepareCallback;
+
+  private boolean deferOnPrepared;
+  private boolean prepared;
   private long seekOffsetUs;
   private long discontinuityPositionUs;
 
+  /**
+   * @param trackGroupArray The track group array.
+   */
   public FakeMediaPeriod(TrackGroupArray trackGroupArray) {
+    this(trackGroupArray, false);
+  }
+
+  /**
+   * @param trackGroupArray The track group array.
+   * @param deferOnPrepared Whether {@link MediaPeriod.Callback#onPrepared(MediaPeriod)} should be
+   *     called only after {@link #setPreparationComplete()} has been called. If {@code false}
+   *     preparation completes immediately.
+   */
+  public FakeMediaPeriod(TrackGroupArray trackGroupArray, boolean deferOnPrepared) {
     this.trackGroupArray = trackGroupArray;
+    this.deferOnPrepared = deferOnPrepared;
     discontinuityPositionUs = C.TIME_UNSET;
   }
 
@@ -52,6 +72,22 @@ public class FakeMediaPeriod implements MediaPeriod {
   }
 
   /**
+   * Allows the fake media period to complete preparation. May be called on any thread.
+   */
+  public synchronized void setPreparationComplete() {
+    deferOnPrepared = false;
+    if (playerHandler != null && prepareCallback != null) {
+      playerHandler.post(new Runnable() {
+        @Override
+        public void run() {
+          prepared = true;
+          prepareCallback.onPrepared(FakeMediaPeriod.this);
+        }
+      });
+    }
+  }
+
+  /**
    * Sets an offset to be applied to positions returned by {@link #seekToUs(long)}.
    *
    * @param seekOffsetUs The offset to be applied, in microseconds.
@@ -61,31 +97,35 @@ public class FakeMediaPeriod implements MediaPeriod {
   }
 
   public void release() {
-    preparedPeriod = false;
+    prepared = false;
   }
 
   @Override
-  public void prepare(Callback callback, long positionUs) {
-    Assert.assertFalse(preparedPeriod);
-    preparedPeriod = true;
-    callback.onPrepared(this);
+  public synchronized void prepare(Callback callback, long positionUs) {
+    if (deferOnPrepared) {
+      playerHandler = new Handler();
+      prepareCallback = callback;
+    } else {
+      prepared = true;
+      callback.onPrepared(this);
+    }
   }
 
   @Override
   public void maybeThrowPrepareError() throws IOException {
-    Assert.assertTrue(preparedPeriod);
+    // Do nothing.
   }
 
   @Override
   public TrackGroupArray getTrackGroups() {
-    Assert.assertTrue(preparedPeriod);
+    Assert.assertTrue(prepared);
     return trackGroupArray;
   }
 
   @Override
   public long selectTracks(TrackSelection[] selections, boolean[] mayRetainStreamFlags,
       SampleStream[] streams, boolean[] streamResetFlags, long positionUs) {
-    Assert.assertTrue(preparedPeriod);
+    Assert.assertTrue(prepared);
     int rendererCount = selections.length;
     for (int i = 0; i < rendererCount; i++) {
       if (streams[i] != null && (selections[i] == null || !mayRetainStreamFlags[i])) {
@@ -113,7 +153,7 @@ public class FakeMediaPeriod implements MediaPeriod {
 
   @Override
   public long readDiscontinuity() {
-    Assert.assertTrue(preparedPeriod);
+    Assert.assertTrue(prepared);
     long positionDiscontinuityUs = this.discontinuityPositionUs;
     this.discontinuityPositionUs = C.TIME_UNSET;
     return positionDiscontinuityUs;
@@ -121,25 +161,25 @@ public class FakeMediaPeriod implements MediaPeriod {
 
   @Override
   public long getBufferedPositionUs() {
-    Assert.assertTrue(preparedPeriod);
+    Assert.assertTrue(prepared);
     return C.TIME_END_OF_SOURCE;
   }
 
   @Override
   public long seekToUs(long positionUs) {
-    Assert.assertTrue(preparedPeriod);
+    Assert.assertTrue(prepared);
     return positionUs + seekOffsetUs;
   }
 
   @Override
   public long getNextLoadPositionUs() {
-    Assert.assertTrue(preparedPeriod);
+    Assert.assertTrue(prepared);
     return C.TIME_END_OF_SOURCE;
   }
 
   @Override
   public boolean continueLoading(long positionUs) {
-    Assert.assertTrue(preparedPeriod);
+    Assert.assertTrue(prepared);
     return false;
   }