@Test
    @LoadGraphWith(MODERN)
    public void g_E_hasLabelXknowsX() {
        final Traversal<Edge, Edge> traversal = get_g_E_hasLabelXknowsX();
        printTraversalForm(traversal);
        int counter = 0;
        while (traversal.hasNext()) {
            counter++;
            assertEquals("knows", traversal.next().label());
        }
        assertEquals(2, counter);
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/filter/HasTest.java