@Test
public void testRemoveUnpreparedChildSourceWithLazyPreparation() throws IOException {

  FakeMediaSource[] childSources = createMediaSources(/* count= */ 2);
  mediaSource =
      new ConcatenatingMediaSource(
          /* isAtomic= */ false,
          /* useLazyPreparation= */ true,
          new DefaultShuffleOrder(0),
          childSources);
  testRunner = new MediaSourceTestRunner(mediaSource, /* allocator= */ null);
  testRunner.prepareSource();
  // Check that removal doesn't throw even though the child sources are unprepared.
  mediaSource.removeMediaSource(0);
}