@Override
            public void edgeAdded(final Edge element) {
                assertThat(element, instanceOf(ReferenceEdge.class));
                assertEquals("self", element.label());
                assertEquals(id, element.inVertex().id());
                assertEquals(id, element.outVertex().id());
                assertThat(element.properties().hasNext(), is(false));
                triggered.set(true);
            }
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/strategy/decoration/EventStrategyProcessTest.java