@Test
    public void shouldNotGenerateVerticesOrEdgesForGraphVariables() {
        graph.tx().readWrite();
        graph.variables().set("namespace", "rdf-xml");
        tryCommit(graph, graph -> {
            assertEquals("rdf-xml", graph.variables().get("namespace").get());
            assertEquals(0, g.V().count().next().intValue());
            assertEquals(0, g.E().count().next().intValue());
            assertEquals(0, IteratorUtils.count(this.getBaseGraph().allNodes()));
            assertEquals(0, IteratorUtils.count(this.getBaseGraph().allRelationships()));
        });
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
neo4j-gremlin/src/test/java/org/apache/tinkerpop/gremlin/neo4j/structure/NativeNeo4jStructureCheck.java