@Test
        @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_ADD_VERTICES)
        @FeatureRequirement(featureClass = VertexFeatures.class, feature = FEATURE_USER_SUPPLIED_IDS)
        public void shouldEvaluateEquivalentVertexHashCodeWithSuppliedIds() {
            final Vertex v = graph.addVertex(T.id, graphProvider.convertId("1", Vertex.class));
            final Vertex u = graph.vertices(graphProvider.convertId("1", Vertex.class)).next();
            assertEquals(v, u);

            final Set<Vertex> set = new HashSet<>();
            set.add(v);
            set.add(v);
            set.add(u);
            set.add(u);
            set.add(graph.vertices(graphProvider.convertId("1", Vertex.class)).next());
            set.add(graph.vertices(graphProvider.convertId("1", Vertex.class)).next());

            assertEquals(1, set.size());
            assertEquals(v.hashCode(), u.hashCode());
        }
@author Marko A. Rodriguez (http://markorodriguez.com)
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/structure/VertexTest.java