public int indexOf(final String str) {
        return indexOf(str, 0);
    }
@Test
    public void testIndexOf() {
        final UnicodeHelper lh = new UnicodeHelper("a", Method.CODEPOINTS);
        assertEquals(-1, lh.indexOf("b"));

        final UnicodeHelper lh2 = new UnicodeHelper(
                "a" + new String(Character.toChars(0x1f600)) + "a" + UCSTR + "A" + "k\u035fh" + "z"
                                                    + "a" + new String(Character.toChars(0x1f600)) + "a" + UCSTR + "A"
                                                    + "k\u035fh" + "z",
                Method.CODEPOINTS);

        assertEquals(1, lh2.indexOf(new String(Character.toChars(0x1f600))));
        assertEquals(14, lh2.indexOf(new String(Character.toChars(0x1f600)), 13));

        assertEquals(3, lh2.indexOf(UCSTR));
        assertEquals(16, lh2.indexOf(UCSTR, 13));

        assertEquals(10, lh2.indexOf("\u035f"));
        assertEquals(23, lh2.indexOf("\u035f", 13));
    }