public void testAddUniqueVertex() {
IndexableGraph graph = new TinkerGraph();
Vertex marko = graph.addVertex(0);
marko.setProperty("name", "marko");
Index<Vertex> index = graph.createIndex("txIdx", Vertex.class);
index.put("name", "marko", marko);
Vertex vertex = IndexableGraphHelper.addUniqueVertex(graph, null, index, "name", "marko");
assertEquals(vertex.getProperty("name"), "marko");
assertEquals(vertex, graph.getVertex(0));
assertEquals(count(graph.getVertices()), 1);