});
    }

    assertThrows(
        NumberFormatException.class,
        () -> UnsignedLongs.parseUnsignedLong("1234567890abcdef1", 16));
  }

  public void testParseLongThrowsExceptionForInvalidRadix() {
    // Valid radix values are Character.MIN_RADIX to Character.MAX_RADIX, inclusive.
    assertThrows(
        NumberFormatException.class,