} catch (NullPointerException expected) {
      // pass
    }
  }

  /**
   * Tests that specifying any alphanumeric characters as 'safe' causes an {@link
   * IllegalArgumentException}.
   */
  public void testBadArguments_badchars() {
    String msg =
        "Alphanumeric characters are always 'safe' " + "and should not be explicitly specified";
    try {
      new PercentEscaper("-+#abc.!", false);

    } catch (NullPointerException expected) {
      // pass
    }
  }

  /**
   * Tests that specifying any alphanumeric characters as 'safe' causes an {@link
   * IllegalArgumentException}.
   */
  public void testBadArguments_badchars() {
    String msg =
        "Alphanumeric characters are always 'safe' " + "and should not be explicitly specified";
    try {
      new PercentEscaper("-+#abc.!", false);

    // TODO(dbeaumont): Support escapers where alphanumeric chars are not safe.
    checkNotNull(safeChars); // eager for GWT.
    // Avoid any misunderstandings about the behavior of this escaper
    if (safeChars.matches(".*[0-9A-Za-z].*")) {
      throw new IllegalArgumentException(
          "Alphanumeric characters are always 'safe' and should not be explicitly specified");
    }