Status status = env_->CreateDir(dirpath);
  if (!status.ok()) GTEST_SKIP() << "CreateDir() not supported: " << status;

  // If updating, make sure to update expected_children below.
  const std::vector<std::string> filenames = {
      GetURIForPath("dir/a_file"),
      GetURIForPath("dir/another_file"),
  };
  for (const auto& filename : filenames) {