private void verifyListenerOnReadException(CacheKey key, IOException exception) {
    ArgumentCaptor<CacheEvent> cacheEventCaptor = ArgumentCaptor.forClass(CacheEvent.class);
    mCacheEventListenerInOrder
        .verify(mCacheEventListener)
        .onReadException(cacheEventCaptor.capture());

    CacheEventAssert.assertThat(cacheEventCaptor.getValue())
        .isNotNull()
        .hasCacheKey(key)
        .hasException(exception);
  }
Verify that multiple threads can write to the cache at the same time.
imagepipeline-base/src/test/java/com/facebook/cache/disk/DiskStorageCacheTest.java