s = fs->CreateDir(root_dir_);
    if (!s.ok()) {
      GTEST_SKIP() << "Cannot create working directory: " << s;
    }
  }

  // Converts path reference to URI reference.
  //
  // If URI scheme is empty, URI reference is `path` relative to current test
  // root directory. Otherwise, we need to add the `<scheme>://` in front of
  // this path.
  //

/// that are supported).

/// This structure incorporates the operations defined in Section 2 and the
/// metadata defined in section 3, allowing plugins to define different ops
/// for different URI schemes.
///
/// Every URI scheme is of the form "fs" for URIs of form "fs:///path/to/file".
/// For local filesystems (i.e., when the URI is "/path/to/file"), the scheme