@Test
  public void vertexIndexLookupWithValue() {
    OrientGraph graph = newGraph();
    createVertexIndexLabel1(graph);
    String value = "value1";

    // verify index created
    Assert.assertEquals(
        graph.getIndexedKeys(Vertex.class, label1), new HashSet<>(Collections.singletonList(key)));
    Assert.assertEquals(
        graph.getIndexedKeys(Vertex.class, label2), new HashSet<>(Collections.emptyList()));
    Assert.assertEquals(
        graph.getIndexedKeys(Edge.class, label1), new HashSet<>(Collections.emptyList()));

    Vertex v1 = graph.addVertex(T.label, label1, key, value);
    Vertex v2 = graph.addVertex(T.label, label2, key, value);

    // looking deep into the internals here - I can't find a nicer way to
    // auto verify that an index is actually used
    GraphTraversal<Vertex, Vertex> traversal =
        graph.traversal().V().has(T.label, P.eq(label1)).has(key, P.eq(value));
    OrientGraphStepStrategy.instance().apply(traversal.asAdmin());

    OrientGraphStep orientGraphStep = (OrientGraphStep) traversal.asAdmin().getStartStep();
    OrientIndexQuery orientIndexQuery = (OrientIndexQuery) orientGraphStep.findIndex().get();

    OIndex index = orientIndexQuery.index;
    Assert.assertEquals(1, index.getSize());
    Assert.assertEquals(v1.id(), index.get(value));
  }