public static void toLowerCase(StringValue string) {
        final char[] chars = string.getCharArray();
        final int len = string.length();

        for (int i = 0; i < len; i++) {
            chars[i] = Character.toLowerCase(chars[i]);
        }
    }
@Test
    void testToLowerCaseConverting() {
        StringValue testString = new StringValue("TEST");
        StringValueUtils.toLowerCase(testString);
        assertThat((Object) testString).isEqualTo(new StringValue("test"));
    }