@Test
public void execute_withPartiallyPopulatedDiskCache_shouldReturnSomeImagesInMap() throws Exception {

    CacheService.initialize(context);
    CacheServiceTest.assertCachesAreEmpty();
    CacheService.putToDiskCache(url1, imageData1.getBytes());
    new ImageDiskTaskManager(list, imageTaskManagerListener, TEST_WIDTH).execute();
    semaphore.acquire();
    assertThat(bitmaps.size()).isEqualTo(2);
    assertThat(bitmaps.get(url1)).isNotNull();
    assertThat(bitmaps.containsKey(url2)).isTrue();
    assertThat(bitmaps.get(url2)).isNull();
}