DownloadHelperTest Failed

[REQUIRED] Issue description

When I try to run ExoPlayer library core test cases keep failing

[REQUIRED] Reproduction steps

When try to Run DownloadHelperTest.java is keep failing

[REQUIRED] Link to test content

N/A

[REQUIRED] A full bug report captured from the device

[Robolectric] com.google.android.exoplayer2.offline.DownloadHelperTest.getTrackSelections_afterReplaceTrackSelections_returnsNewSelections: sdk=28; resources=BINARY
Exception in thread "DownloadHelper" java.lang.NullPointerException
	at com.google.android.exoplayer2.offline.DownloadHelper$MediaPreparer.onSourceInfoRefreshed(DownloadHelper.java:918)
	at com.google.android.exoplayer2.source.BaseMediaSource.refreshSourceInfo(BaseMediaSource.java:74)
	at com.google.android.exoplayer2.testutil.FakeMediaSource.finishSourcePreparation(FakeMediaSource.java:215)
	at com.google.android.exoplayer2.testutil.FakeMediaSource.prepareSourceInternal(FakeMediaSource.java:105)
	at com.google.android.exoplayer2.source.BaseMediaSource.prepareSource(BaseMediaSource.java:140)
	at com.google.android.exoplayer2.offline.DownloadHelper$MediaPreparer.handleMessage(DownloadHelper.java:858)
	at android.os.Handler.dispatchMessage(Handler.java:102)
	at com.google.android.exoplayer2.testutil.RobolectricUtil$CustomLooper.doLoop(RobolectricUtil.java:129)
	at com.google.android.exoplayer2.testutil.RobolectricUtil$CustomLooper.loop(RobolectricUtil.java:67)
	at android.os.Looper.loop(Looper.java)
	at android.os.HandlerThread.run(HandlerThread.java:65)

[REQUIRED] Version of ExoPlayer being used

2.10.2

[REQUIRED] Device(s) and version(s) of Android being used

N/A

[ojw28]

Yes, we’ll push a fix for this shortly. Thanks for the bug report!

[drayan85]

Thanks, @ojw28. I have shifted the pendingMediaPeriods = new ArrayList<>() initialization above the mediaSourceThread.start() in the DownloadHelper.java as below.

    public MediaPreparer(MediaSource mediaSource, DownloadHelper downloadHelper) {
      this.mediaSource = mediaSource;
      this.downloadHelper = downloadHelper;
      allocator = new DefaultAllocator(true, C.DEFAULT_BUFFER_SEGMENT_SIZE);
      @SuppressWarnings("methodref.receiver.bound.invalid")
      Handler downloadThreadHandler = Util.createHandler(this::handleDownloadHelperCallbackMessage);
      this.downloadHelperHandler = downloadThreadHandler;
      mediaSourceThread = new HandlerThread("DownloadHelper");
      pendingMediaPeriods = new ArrayList<>();
      mediaSourceThread.start();
      mediaSourceHandler = Util.createHandler(mediaSourceThread.getLooper(), /* callback= */ this);
      mediaSourceHandler.sendEmptyMessage(MESSAGE_PREPARE_SOURCE);
    }

No all the test suits pass successfully.