@Test(expected = IllegalStateException.class)
    public void allGraphFails() {
        settings.graphs = settings.graphs.keySet().stream()
                .collect(toMap(Function.identity(), name -> "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