@Test
    @LoadGraphWith(LoadGraphWith.GraphData.MODERN)
    public void shouldNotHaveAnyVertices() {
        final ReferenceVertex rv = ReferenceFactory.detach(g.V(convertToVertexId("marko")).next());
        assertFalse(rv.vertices(Direction.BOTH).hasNext());
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/structure/util/reference/ReferenceVertexTest.java