@Override
        public void workerStart(final Stage stage) {
            WORKER_START.add(stage);
            if (!stage.equals(Stage.MAP))
                assertFalse(WORKER_END.isEmpty());
        }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/computer/GraphComputerTest.java