}

    public void test_convertMixedText() {
        List<String> results = converter.convert("トウキョウ", null);
        assertTrue(results.contains("toukyou"));
    }

    public void test_convertWithNumbers() {
        List<String> results = converter.convert("テスト123", null);
        assertNotNull(results);
        assertTrue(results.size() > 0);
    }

    public void test_convertLowercase() {