private String normalize(String url) {
        return normalizer.normalize(url);
    }

    @Test
    void testNullSafe() {
        assertNull(normalize(null));
    }

    @Test
    void testTrailingSlash() {
        assertEquals("", normalize(""));
        assertEquals("http://server.org/dir", normalize("http://server.org/dir"));
        assertEquals("http://server.org/dir/", normalize("http://server.org/dir/"));
    }