@Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.SIMPLE)
    public void shouldHashAndEqualCorrectly() {
        final Vertex v = graph.addVertex();
        final Edge e = v.addEdge("test", v);
        final Set<Edge> set = new HashSet<>();
        for (int i = 0; i < 100; i++) {
            set.add(ReferenceFactory.detach(e));
            set.add(e);
        }
        assertEquals(1, set.size());
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/structure/util/reference/ReferenceEdgeTest.java