@Test public final void roundTrip() {

    String ns = "http://www.a.com/foo/";
    Model m = simpleModel(ns);
    m.setNsPrefix("ex", ns);
    for (RDFFormat f : JSON_LD_FORMATS) {
        if (((RDFFormat.JSONLDVariant) f.getVariant()).isFrame()) continue;
        String s = toString(m, f, null);
        Model m2 = parse(s);
        assertTrue(m2.isIsomorphicWith(m));        
    }
}