    @Test
    public void getSuffixYinUnU_forMasculineWordEndingWithVowel_OE() {

        char wordLastChar = MongolCode.Uni.OE;
        String result = MongolCode.getSuffixYinUnU(MongolCode.Gender.MASCULINE, wordLastChar);
        String expected = MongolCode.Suffix.YIN;
        assertEquals(expected, result);
    }