@Test
    @LoadGraphWith(MODERN)
    public void g_V_hasXlangX_group_byXlangX_byXcountX() {
        final Traversal<Vertex, Map<String, Long>> traversal = get_g_V_hasXlangX_group_byXlangX_byXcountX();
        printTraversalForm(traversal);
        final Map<String, Long> map = traversal.next();
        assertEquals(1, map.size());
        assertTrue(map.containsKey("java"));
        assertEquals(Long.valueOf(2), map.get("java"));
        assertFalse(traversal.hasNext());
        checkSideEffects(traversal.asAdmin().getSideEffects());
    }
@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/sideEffect/GroupTest.java