@Test
    @LoadGraphWith(MODERN)
    public void g_V_valueMap_unfold_mapXkeyX() {
        final Traversal<Vertex, String> traversal = get_g_V_valueMap_unfold_mapXkeyX();
        printTraversalForm(traversal);
        int counter = 0;
        int ageCounter = 0;
        int nameCounter = 0;
        int langCounter = 0;
        while (traversal.hasNext()) {
            counter++;
            final String key = traversal.next();
            if (key.equals("name"))
                nameCounter++;
            else if (key.equals("age"))
                ageCounter++;
            else if (key.equals("lang"))
                langCounter++;
            else
                fail("The provided key is not known: " + key);
        }
        assertEquals(12, counter);
        assertEquals(4, ageCounter);
        assertEquals(2, langCounter);
        assertEquals(6, nameCounter);
        assertEquals(counter, ageCounter + langCounter + nameCounter);
        assertFalse(traversal.hasNext());
    }
Tests that cover lambda steps that are used in embedded cases.
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/LambdaStepTest.java