Make FakeRenderer more realistic

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=183643457

library/core/src/test/java/com/google/android/exoplayer2/DefaultMediaClockTest.java

@@ -379,10 +379,12 @@ public class DefaultMediaClockTest {
 
   private static class MediaClockRenderer extends FakeMediaClockRenderer {
 
-    public long positionUs;
-    public PlaybackParameters playbackParameters;
-
     private final boolean playbackParametersAreMutable;
+    private final boolean isReady;
+    private final boolean isEnded;
+
+    public PlaybackParameters playbackParameters;
+    public long positionUs;
 
     public MediaClockRenderer() throws ExoPlaybackException {
       this(PlaybackParameters.DEFAULT, false, true, false, false);
@@ -403,11 +405,11 @@ public class DefaultMediaClockTest {
         boolean playbackParametersAreMutable, boolean isReady, boolean isEnded,
         boolean hasReadStreamToEnd)
         throws ExoPlaybackException {
-      this.positionUs = TEST_POSITION_US;
       this.playbackParameters = playbackParameters;
       this.playbackParametersAreMutable = playbackParametersAreMutable;
       this.isReady = isReady;
       this.isEnded = isEnded;
+      this.positionUs = TEST_POSITION_US;
       if (!hasReadStreamToEnd) {
         resetPosition(0);
       }
@@ -436,6 +438,10 @@ public class DefaultMediaClockTest {
       return isReady;
     }
 
+    @Override
+    public boolean isEnded() {
+      return isEnded;
+    }
   }
 
 }

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

@@ -85,7 +85,7 @@ public final class ExoPlayerTest {
     testRunner.assertNoPositionDiscontinuities();
     testRunner.assertTimelinesEqual(timeline);
     assertThat(renderer.formatReadCount).isEqualTo(0);
-    assertThat(renderer.bufferReadCount).isEqualTo(0);
+    assertThat(renderer.sampleBufferReadCount).isEqualTo(0);
     assertThat(renderer.isEnded).isFalse();
   }
 
@@ -109,7 +109,7 @@ public final class ExoPlayerTest {
     testRunner.assertTimelineChangeReasonsEqual(Player.TIMELINE_CHANGE_REASON_PREPARED);
     testRunner.assertTrackGroupsEqual(new TrackGroupArray(new TrackGroup(Builder.VIDEO_FORMAT)));
     assertThat(renderer.formatReadCount).isEqualTo(1);
-    assertThat(renderer.bufferReadCount).isEqualTo(1);
+    assertThat(renderer.sampleBufferReadCount).isEqualTo(1);
     assertThat(renderer.isEnded).isTrue();
   }
 
@@ -131,7 +131,7 @@ public final class ExoPlayerTest {
     testRunner.assertTimelinesEqual(timeline);
     testRunner.assertTimelineChangeReasonsEqual(Player.TIMELINE_CHANGE_REASON_PREPARED);
     assertThat(renderer.formatReadCount).isEqualTo(3);
-    assertThat(renderer.bufferReadCount).isEqualTo(1);
+    assertThat(renderer.sampleBufferReadCount).isEqualTo(3);
     assertThat(renderer.isEnded).isTrue();
   }
 
@@ -155,7 +155,7 @@ public final class ExoPlayerTest {
     testRunner.assertTimelinesEqual(timeline);
     testRunner.assertTimelineChangeReasonsEqual(Player.TIMELINE_CHANGE_REASON_PREPARED);
     assertThat(renderer.formatReadCount).isEqualTo(100);
-    assertThat(renderer.bufferReadCount).isEqualTo(1);
+    assertThat(renderer.sampleBufferReadCount).isEqualTo(100);
     assertThat(renderer.isEnded).isTrue();
   }
 

library/core/src/test/java/com/google/android/exoplayer2/audio/SimpleDecoderAudioRendererTest.java

@@ -90,8 +90,13 @@ public class SimpleDecoderAudioRendererTest {
 
   @Test
   public void testImmediatelyReadEndOfStreamPlaysAudioSinkToEndOfStream() throws Exception {
-    audioRenderer.enable(RendererConfiguration.DEFAULT, new Format[] {FORMAT},
-        new FakeSampleStream(FORMAT), 0, false, 0);
+    audioRenderer.enable(
+        RendererConfiguration.DEFAULT,
+        new Format[] {FORMAT},
+        new FakeSampleStream(FORMAT, false),
+        0,
+        false,
+        0);
     audioRenderer.setCurrentStreamFinal();
     when(mockAudioSink.isEnded()).thenReturn(true);
     while (!audioRenderer.isEnded()) {
@@ -116,7 +121,7 @@ public class SimpleDecoderAudioRendererTest {
 
     @Override
     protected DecoderInputBuffer createInputBuffer() {
-      return new DecoderInputBuffer(DecoderInputBuffer.BUFFER_REPLACEMENT_MODE_DISABLED);
+      return new DecoderInputBuffer(DecoderInputBuffer.BUFFER_REPLACEMENT_MODE_DIRECT);
     }
 
     @Override

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

@@ -24,6 +24,7 @@ import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.FormatHolder;
 import com.google.android.exoplayer2.Renderer;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.MimeTypes;
 import java.util.Arrays;
 import java.util.Collections;
@@ -35,51 +36,72 @@ import java.util.List;
  */
 public class FakeRenderer extends BaseRenderer {
 
+  /**
+   * The amount of time ahead of the current playback position that the renderer reads from the
+   * source. A real renderer will typically read ahead by a small amount due to pipelining through
+   * decoders and the media output path.
+   */
+  private static final long SOURCE_READAHEAD_US = 250000;
+
   private final List<Format> expectedFormats;
   private final DecoderInputBuffer buffer;
+  private final FormatHolder formatHolder;
 
+  private long playbackPositionUs;
+  private long lastSamplePositionUs;
+
+  public boolean isEnded;
   public int positionResetCount;
   public int formatReadCount;
-  public int bufferReadCount;
-  public boolean isEnded;
-  public boolean isReady;
+  public int sampleBufferReadCount;
 
   public FakeRenderer(Format... expectedFormats) {
     super(expectedFormats.length == 0 ? C.TRACK_TYPE_UNKNOWN
         : MimeTypes.getTrackType(expectedFormats[0].sampleMimeType));
     this.expectedFormats = Collections.unmodifiableList(Arrays.asList(expectedFormats));
-    this.buffer = new DecoderInputBuffer(DecoderInputBuffer.BUFFER_REPLACEMENT_MODE_NORMAL);
+    buffer = new DecoderInputBuffer(DecoderInputBuffer.BUFFER_REPLACEMENT_MODE_NORMAL);
+    formatHolder = new FormatHolder();
+    lastSamplePositionUs = Long.MIN_VALUE;
   }
 
   @Override
   protected void onPositionReset(long positionUs, boolean joining) throws ExoPlaybackException {
+    playbackPositionUs = positionUs;
+    lastSamplePositionUs = Long.MIN_VALUE;
     positionResetCount++;
     isEnded = false;
   }
 
   @Override
   public void render(long positionUs, long elapsedRealtimeUs) throws ExoPlaybackException {
-    if (!isEnded) {
-      // Verify the format matches the expected format.
-      FormatHolder formatHolder = new FormatHolder();
+    if (isEnded) {
+      return;
+    }
+    playbackPositionUs = positionUs;
+    while (lastSamplePositionUs < positionUs + SOURCE_READAHEAD_US) {
+      formatHolder.format = null;
+      buffer.clear();
       int result = readSource(formatHolder, buffer, false);
-      buffer.data = null;
       if (result == C.RESULT_FORMAT_READ) {
         formatReadCount++;
         assertThat(expectedFormats).contains(formatHolder.format);
       } else if (result == C.RESULT_BUFFER_READ) {
-        bufferReadCount++;
         if (buffer.isEndOfStream()) {
           isEnded = true;
+          return;
         }
+        lastSamplePositionUs = buffer.timeUs;
+        sampleBufferReadCount++;
+      } else {
+        Assertions.checkState(result == C.RESULT_NOTHING_READ);
+        return;
       }
     }
-    isReady = buffer.timeUs >= positionUs || hasReadStreamToEnd();
   }
 
   @Override
   public boolean isReady() {
-    return isReady || isSourceReady();
+    return lastSamplePositionUs >= playbackPositionUs || isSourceReady();
   }
 
   @Override

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

@@ -23,17 +23,23 @@ import com.google.android.exoplayer2.source.SampleStream;
 import java.io.IOException;
 
 /**
- * Fake {@link SampleStream} that outputs a given {@link Format} then sets the end of stream flag
- * on its input buffer.
+ * Fake {@link SampleStream} that outputs a given {@link Format}, an optional sample containing a
+ * single zero byte, then end of stream.
  */
 public final class FakeSampleStream implements SampleStream {
 
   private final Format format;
 
   private boolean readFormat;
+  private boolean readSample;
 
   public FakeSampleStream(Format format) {
+    this(format, true);
+  }
+
+  public FakeSampleStream(Format format, boolean shouldOutputSample) {
     this.format = format;
+    readSample = !shouldOutputSample;
   }
 
   @Override
@@ -48,6 +54,13 @@ public final class FakeSampleStream implements SampleStream {
       formatHolder.format = format;
       readFormat = true;
       return C.RESULT_FORMAT_READ;
+    } else if (!readSample) {
+      buffer.timeUs = 0;
+      buffer.ensureSpaceForWrite(1);
+      buffer.data.put((byte) 0);
+      buffer.flip();
+      readSample = true;
+      return C.RESULT_BUFFER_READ;
     } else {
       buffer.setFlags(C.BUFFER_FLAG_END_OF_STREAM);
       return C.RESULT_BUFFER_READ;