@Test
    @LoadGraphWith(MODERN)
    public void g_injectXnull_10_20_nullX_mean() {
        final Traversal<Integer, Double> traversal = get_g_injectXnull_10_20_nullX_mean();
        printTraversalForm(traversal);
        final Double mean = traversal.next();
        assertEquals(15.00, mean, 0.05);
        assertFalse(traversal.hasNext());
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/MeanTest.java