Add multi-period ExoPlayer unit test

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=143475824

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

@@ -21,7 +21,6 @@ import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
 import com.google.android.exoplayer2.source.MediaPeriod;
 import com.google.android.exoplayer2.source.MediaSource;
 import com.google.android.exoplayer2.source.SampleStream;
-import com.google.android.exoplayer2.source.SinglePeriodTimeline;
 import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
@@ -49,16 +48,9 @@ public final class ExoPlayerTest extends TestCase {
    */
   private static final int TIMEOUT_MS = 10000;
 
-  /**
+  private static final Format TEST_VIDEO_FORMAT = Format.createVideoSampleFormat(null,
-   * Tests playback of a source that exposes a single period.
+      MimeTypes.VIDEO_H264, null, Format.NO_VALUE, Format.NO_VALUE, 1280, 720, Format.NO_VALUE,
-   */
+      null, null);
-  public void testPlayToEnd() throws Exception {
-    PlayerWrapper playerWrapper = new PlayerWrapper();
-    Format format = Format.createVideoSampleFormat(null, MimeTypes.VIDEO_H264, null,
-        Format.NO_VALUE, Format.NO_VALUE, 1280, 720, Format.NO_VALUE, null, null);
-    playerWrapper.setup(new SinglePeriodTimeline(0, false), null, format);
-    playerWrapper.blockUntilEnded(TIMEOUT_MS);
-  }
 
   /**
    * Tests playback of a source that exposes an empty timeline. Playback is expected to end without
@@ -68,6 +60,42 @@ public final class ExoPlayerTest extends TestCase {
     PlayerWrapper playerWrapper = new PlayerWrapper();
     playerWrapper.setup(Timeline.EMPTY, null, null);
     playerWrapper.blockUntilEnded(TIMEOUT_MS);
+    assertEquals(0, playerWrapper.positionDiscontinuityCount);
+    assertEquals(0, playerWrapper.videoRenderer.formatReadCount);
+    assertEquals(0, playerWrapper.videoRenderer.bufferReadCount);
+    assertFalse(playerWrapper.videoRenderer.isEnded);
+  }
+
+  /**
+   * Tests playback of a source that exposes a single period.
+   */
+  public void testPlaySinglePeriodTimeline() throws Exception {
+    PlayerWrapper playerWrapper = new PlayerWrapper();
+    Timeline timeline = new FakeTimeline(
+        new TimelineWindowDefinition(false, false, 0));
+    playerWrapper.setup(timeline, null, TEST_VIDEO_FORMAT);
+    playerWrapper.blockUntilEnded(TIMEOUT_MS);
+    assertEquals(0, playerWrapper.positionDiscontinuityCount);
+    assertEquals(1, playerWrapper.videoRenderer.formatReadCount);
+    assertEquals(1, playerWrapper.videoRenderer.bufferReadCount);
+    assertTrue(playerWrapper.videoRenderer.isEnded);
+  }
+
+  /**
+   * Tests playback of a source that exposes three periods.
+   */
+  public void testPlayMultiPeriodTimeline() throws Exception {
+    PlayerWrapper playerWrapper = new PlayerWrapper();
+    Timeline timeline = new FakeTimeline(
+        new TimelineWindowDefinition(false, false, 0),
+        new TimelineWindowDefinition(false, false, 0),
+        new TimelineWindowDefinition(false, false, 0));
+    playerWrapper.setup(timeline, null, TEST_VIDEO_FORMAT);
+    playerWrapper.blockUntilEnded(TIMEOUT_MS);
+    assertEquals(2, playerWrapper.positionDiscontinuityCount);
+    assertEquals(3, playerWrapper.videoRenderer.formatReadCount);
+    assertEquals(1, playerWrapper.videoRenderer.bufferReadCount);
+    assertTrue(playerWrapper.videoRenderer.isEnded);
   }
 
   /**
@@ -82,9 +110,12 @@ public final class ExoPlayerTest extends TestCase {
     private Timeline expectedTimeline;
     private Object expectedManifest;
     private Format expectedFormat;
+    private FakeVideoRenderer videoRenderer;
     private ExoPlayer player;
     private Exception exception;
 
+    private int positionDiscontinuityCount;
+
     public PlayerWrapper() {
       endedCountDownLatch = new CountDownLatch(1);
       playerThread = new HandlerThread("ExoPlayerTest thread");
@@ -113,8 +144,8 @@ public final class ExoPlayerTest extends TestCase {
         @Override
         public void run() {
           try {
-            Renderer fakeRenderer = new FakeVideoRenderer(expectedFormat);
+            videoRenderer = new FakeVideoRenderer(expectedFormat);
-            player = ExoPlayerFactory.newInstance(new Renderer[] {fakeRenderer},
+            player = ExoPlayerFactory.newInstance(new Renderer[] {videoRenderer},
                 new DefaultTrackSelector());
             player.addListener(PlayerWrapper.this);
             player.setPlayWhenReady(true);
@@ -184,8 +215,66 @@ public final class ExoPlayerTest extends TestCase {
 
     @Override
     public void onPositionDiscontinuity() {
-      // Should never happen.
+      positionDiscontinuityCount++;
-      handleError(new IllegalStateException("Received position discontinuity"));
+    }
+
+  }
+
+  private static final class TimelineWindowDefinition {
+
+    public final boolean isSeekable;
+    public final boolean isDynamic;
+    public final long durationUs;
+
+    public TimelineWindowDefinition(boolean isSeekable, boolean isDynamic, long durationUs) {
+      this.isSeekable = isSeekable;
+      this.isDynamic = isDynamic;
+      this.durationUs = durationUs;
+    }
+
+  }
+
+  private static final class FakeTimeline extends Timeline {
+
+    private final TimelineWindowDefinition[] windowDefinitions;
+
+    public FakeTimeline(TimelineWindowDefinition... windowDefinitions) {
+      this.windowDefinitions = windowDefinitions;
+    }
+
+    @Override
+    public int getWindowCount() {
+      return windowDefinitions.length;
+    }
+
+    @Override
+    public Window getWindow(int windowIndex, Window window, boolean setIds,
+        long defaultPositionProjectionUs) {
+      TimelineWindowDefinition windowDefinition = windowDefinitions[windowIndex];
+      Object id = setIds ? windowIndex : null;
+      return window.set(id, C.TIME_UNSET, C.TIME_UNSET, windowDefinition.isSeekable,
+          windowDefinition.isDynamic, 0, windowDefinition.durationUs, windowIndex, windowIndex, 0);
+    }
+
+    @Override
+    public int getPeriodCount() {
+      return windowDefinitions.length;
+    }
+
+    @Override
+    public Period getPeriod(int periodIndex, Period period, boolean setIds) {
+      TimelineWindowDefinition windowDefinition = windowDefinitions[periodIndex];
+      Object id = setIds ? periodIndex : null;
+      return period.set(id, id, periodIndex, windowDefinition.durationUs, 0);
+    }
+
+    @Override
+    public int getIndexOfPeriod(Object uid) {
+      if (!(uid instanceof Integer)) {
+        return C.INDEX_UNSET;
+      }
+      int index = (Integer) uid;
+      return index >= 0 && index < windowDefinitions.length ? index : C.INDEX_UNSET;
     }
 
   }
@@ -228,7 +317,6 @@ public final class ExoPlayerTest extends TestCase {
       Assertions.checkIndex(index, 0, timeline.getPeriodCount());
       assertTrue(preparedSource);
       assertFalse(releasedSource);
-      assertEquals(0, index);
       assertEquals(0, positionUs);
       FakeMediaPeriod mediaPeriod = new FakeMediaPeriod(format);
       activeMediaPeriods.add(mediaPeriod);
@@ -332,7 +420,7 @@ public final class ExoPlayerTest extends TestCase {
     @Override
     public long getNextLoadPositionUs() {
       assertTrue(preparedPeriod);
-      return 0;
+      return C.TIME_END_OF_SOURCE;
     }
 
     @Override
@@ -352,7 +440,6 @@ public final class ExoPlayerTest extends TestCase {
     private final Format format;
 
     private boolean readFormat;
-    private boolean readEndOfStream;
 
     public FakeSampleStream(Format format) {
       this.format = format;
@@ -365,10 +452,8 @@ public final class ExoPlayerTest extends TestCase {
 
     @Override
     public int readData(FormatHolder formatHolder, DecoderInputBuffer buffer) {
-      Assertions.checkState(!readEndOfStream);
       if (readFormat) {
         buffer.setFlags(C.BUFFER_FLAG_END_OF_STREAM);
-        readEndOfStream = true;
         return C.RESULT_BUFFER_READ;
       }
       formatHolder.format = format;
@@ -390,12 +475,14 @@ public final class ExoPlayerTest extends TestCase {
 
   /**
    * Fake {@link Renderer} that supports any video format. The renderer verifies that it reads a
-   * given {@link Format} then a buffer with the end of stream flag set.
+   * given {@link Format}.
    */
   private static final class FakeVideoRenderer extends BaseRenderer {
 
     private final Format expectedFormat;
 
+    private int formatReadCount;
+    private int bufferReadCount;
     private boolean isEnded;
 
     public FakeVideoRenderer(Format expectedFormat) {
@@ -403,6 +490,11 @@ public final class ExoPlayerTest extends TestCase {
       this.expectedFormat = expectedFormat;
     }
 
+    @Override
+    protected void onPositionReset(long positionUs, boolean joining) throws ExoPlaybackException {
+      isEnded = false;
+    }
+
     @Override
     public void render(long positionUs, long elapsedRealtimeUs) throws ExoPlaybackException {
       if (isEnded) {
@@ -411,20 +503,23 @@ public final class ExoPlayerTest extends TestCase {
 
       // Verify the format matches the expected format.
       FormatHolder formatHolder = new FormatHolder();
-      readSource(formatHolder, null);
-      assertEquals(expectedFormat, formatHolder.format);
-
-      // Verify that we get an end-of-stream buffer.
       DecoderInputBuffer buffer =
           new DecoderInputBuffer(DecoderInputBuffer.BUFFER_REPLACEMENT_MODE_NORMAL);
-      readSource(null, buffer);
+      int result = readSource(formatHolder, buffer);
-      assertTrue(buffer.isEndOfStream());
+      if (result == C.RESULT_FORMAT_READ) {
-      isEnded = true;
+        formatReadCount++;
+        assertEquals(expectedFormat, formatHolder.format);
+      } else if (result == C.RESULT_BUFFER_READ) {
+        bufferReadCount++;
+        if (buffer.isEndOfStream()) {
+          isEnded = true;
+        }
+      }
     }
 
     @Override
     public boolean isReady() {
-      return isEnded;
+      return isSourceReady();
     }
 
     @Override