assertEquals("value1", result.get("test_key"));
        assertEquals("value2", result.get("another_test_key"));

        @SuppressWarnings("unchecked")
        Map<String, Object> nestedResult = (Map<String, Object>) result.get("nested_map");
        assertEquals("nestedValue", nestedResult.get("nested_key"));
    }

    public void test_toLowerHyphen_emptyMap() {
        Map<String, Object> source = new HashMap<>();