@Test
public void testDeleteBuckets() throws IOException {

  List<String> buckets = Lists.newArrayList(BUCKET_A);
  // Prepare the cache.
  cache.putItem(ITEM_A_A); // Deleted.
  cache.putItem(ITEM_B_A); // Not deleted.
  gcs.deleteBuckets(buckets);
  // Verify the delegate call.
  verify(gcsDelegate).deleteBuckets(eq(buckets));
  // Verify the state of the cache.
  assertThat(cache.getAllItemsRaw()).containsExactly(ITEM_B_A);
}