private Region mockRegionWithSize(Collection<Long> storeSizes) {
    final Region r = mock(Region.class);
    final RegionInfo info = mock(RegionInfo.class);
    when(r.getRegionInfo()).thenReturn(info);
    List<Store> stores = new ArrayList<>();
    when(r.getStores()).thenReturn((List) stores);
    for (Long storeSize : storeSizes) {
      final Store s = mock(Store.class);
      stores.add(s);
      when(s.getHFilesSize()).thenReturn(storeSize);
    }
    return r;
  }
Creates a region with a number of Stores equal to the length of {@code storeSizes}. Each
{@link Store} will have a reported size corresponding to the element in {@code storeSizes}.
@param storeSizes A list of sizes for each Store.
@return A mocked Region.
hbase-server/src/test/java/org/apache/hadoop/hbase/quotas/TestFileSystemUtilizationChore.java