assertTrue(results.contains("tsa"));
    }

    public void test_convertModernKatakana_Tse() {
        List<String> results = converter.convert("ツェ", null);
        assertTrue(results.contains("tse"));
    }

    public void test_convertFyu_BugFix() {
        // Test that フュ correctly maps to "fyu" only (not "hyu")
        List<String> results = converter.convert("フュ", null);

        map.put("ッ", new String[] { "tu", "tsu" });

        map.put("ツァ", new String[] { "tsa" });
        map.put("ツィ", new String[] { "tsi" });
        map.put("ツェ", new String[] { "tse" });
        map.put("ツォ", new String[] { "tso" });

        return map;
    }

    private List<StringBuilder> deepCopyBufList(final List<StringBuilder> bufList) {