doTestTrimLeadingFrom("x-x-", "x-x-");
    doTestTrimLeadingFrom("x-xx", "x-xx");
    doTestTrimLeadingFrom("x-x--xx---x----x", "x-x--xx---x----x");
    // additional testing using the doc example
    assertEquals("catbab", anyOf("ab").trimLeadingFrom("abacatbab"));
  }

  private void doTestTrimLeadingFrom(String in, String out) {
    // Try a few different matchers which all match '-' and not 'x'

    doTestTrimLeadingFrom("x-x-", "x-x-");
    doTestTrimLeadingFrom("x-xx", "x-xx");
    doTestTrimLeadingFrom("x-x--xx---x----x", "x-x--xx---x----x");
    // additional testing using the doc example
    assertEquals("catbab", anyOf("ab").trimLeadingFrom("abacatbab"));
  }

  private void doTestTrimLeadingFrom(String in, String out) {
    // Try a few different matchers which all match '-' and not 'x'

        byte[] keyb = Hex.decode(key);
        byte[] datab = data.getBytes(StandardCharsets.US_ASCII);
        byte[] javaMac = sun.security.krb5.internal.crypto.ArcFourHmac.calculateChecksum(keyb, usage, datab, 0, datab.length);
        byte[] mac = PacMac.calculateMacArcfourHMACMD5(usage, makeKey(keyb, 23), datab);
        checkBytes(javaMac, mac);
        checkBytes(Hex.decode(expect), javaMac);