@Override
        public void map(final Vertex vertex, final MapEmitter<NullObject, Integer> emitter) {
            emitter.emit(1);
            assertEquals(1, countTrue(WORKER_START));
            assertTrue(WORKER_START.contains(Stage.MAP));
        }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/computer/GraphComputerTest.java