static RegularFile regularFile(int size) {
    RegularFile file =
        RegularFile.create(0, new FakeFileTimeSource().now(), new HeapDisk(8096, 1000, 1000));
    try {
      file.write(0, new byte[size], 0, size);
      return file;
    } catch (IOException e) {
      throw new AssertionError(e);
    }
  }
Returns a number of permutations of the given path that should all locate the same file.
jimfs/src/test/java/com/google/common/jimfs/TestUtils.java