/**
   * Helper to assert common expected behaviour of uri escapers. You should call
   * assertBasicUrlEscaper() unless the escaper explicitly does not escape '%'.
   */
  static void assertBasicUrlEscaperExceptPercent(UnicodeEscaper e) {
    // URL escapers should throw null pointer exceptions for null input
    try {
      e.escape((String) null);
      fail("Escaping null string should throw exception");