@Test
    public void openGraphShouldReturnExistingGraph() {
        final Settings settings = Settings.read(DefaultGraphManagerTest.class.getResourceAsStream("../gremlin-server-integration.yaml"));
        final GraphManager graphManager = new DefaultGraphManager(settings);

        final Graph graph = graphManager.openGraph("graph", null);
        assertNotNull(graph);
        assertThat(graph, instanceOf(TinkerGraph.class));
    }
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-server/src/test/java/org/apache/tinkerpop/gremlin/server/util/DefaultGraphManagerTest.java