Thread.yield();
          }
        } finally {
          executor.shutdownNow();
        }
      }
    }
  }

  public void testDeleteRecursively_nonDirectoryFile() throws IOException {
    try (FileSystem fs = newTestFileSystem(SECURE_DIRECTORY_STREAM)) {
      Path file = fs.getPath("dir/a");
      assertTrue(Files.isRegularFile(file, NOFOLLOW_LINKS));