@Test
    public void shouldWriteClassicGraphAsGryoV3() throws IOException {
        final OutputStream os = new FileOutputStream(new File(tempPath, "tinkerpop-classic-v3.kryo"));
        GryoWriter.build().mapper(GryoMapper.build().version(GryoVersion.V3_0).create()).create().writeGraph(os, TinkerFactory.createClassic());
        os.close();
    }
No assertions.  Just write out the graph for convenience.
tinkergraph-gremlin/src/test/java/org/apache/tinkerpop/gremlin/tinkergraph/structure/IoDataGenerationTest.java