@Test(expected = IllegalStateException.class)
    public void singleGraphFails() {
        settings.graphs.clear();
        settings.graphs.put("invalid", "conf/invalidPath");
        new CheckedGraphManager(settings);
    }
TINKERPOP-2436 The gremlin server starts even if all graphs instantiation
gremlin-server/src/test/java/org/apache/tinkerpop/gremlin/server/util/CheckedGraphManagerTest.java