@Test
    public void shouldCreateAnEmptyGraphInstance() {
        final Configuration conf = new BaseConfiguration();
        conf.setProperty(Graph.GRAPH, EmptyGraph.class.getName());
        final Graph graph = GraphFactory.open(conf);
        assertSame(EmptyGraph.instance(), graph);
    }
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-core/src/test/java/org/apache/tinkerpop/gremlin/structure/util/GraphFactoryTest.java