/**
     * @throws Exception
     */
    @Test
    public void testRtrim() throws Exception {
        assertEquals("trim", StringUtil.rtrim("trimxxxx", "x"));
        assertEquals("", StringUtil.rtrim("xyz", "xyz"));
        assertEquals("trimxxxx", StringUtil.rtrim("trimxxxx", "y"));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testTrimSuffix() throws Exception {