@Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    public void shouldNotConstructNewWithSomethingAlreadyDetached() {
        final Vertex v = graph.addVertex();
        final DetachedVertex dv = DetachedFactory.detach(v, true);
        assertSame(dv, DetachedFactory.detach(dv, true));
    }
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/structure/util/detached/DetachedVertexTest.java