public static boolean contains(final CharSequence str, final CharSequence searchStr) {
        if (str == null || searchStr == null) {
            return false;
        }
        return str.toString().contains(searchStr);
    }
@Test
    void testContains() {
        assertFalse(StringUtils.contains(null, "1"));
        assertFalse(StringUtils.contains("abc", null));
        assertTrue(StringUtils.contains(StringUtils.EMPTY, StringUtils.EMPTY));
        assertTrue(StringUtils.contains("abc", StringUtils.EMPTY));
        assertTrue(StringUtils.contains("abc", "a"));
        assertFalse(StringUtils.contains("abc", "z"));
        assertFalse(StringUtils.contains("abc", "A"));
        assertFalse(StringUtils.contains("abc", "Z"));
    }