public URLNormalizer secureScheme() {
        Matcher m = PATTERN_SCHEMA.matcher(url);
        if (m.find()) {
            String schema = m.group(1);
            if ("http".equalsIgnoreCase(schema)) {
                url = m.replaceFirst(schema + "s$2");
            }
        }
        return this;
    }
@Test
    public void testSecureScheme() {
        s = "https://www.example.com/secure.html";
        t = "https://www.example.com/secure.html";
        assertEquals(t, n(s).secureScheme().toString());
        s = "HTtP://www.example.com/secure.html";
        t = "HTtPs://www.example.com/secure.html";
        assertEquals(t, n(s).secureScheme().toString());
        s = "HTTP://www.example.com/nonsecure.html";
        t = "HTTPs://www.example.com/nonsecure.html";
        assertEquals(t, n(s).secureScheme().toString());
    }