@Test
    public void shouldEnforceUniqueConstraint() {
        this.graph.tx().readWrite();
        this.getBaseGraph().execute("CREATE CONSTRAINT ON (p:Person) assert p.name is unique", null);
        this.graph.tx().commit();
        this.graph.tx().commit();
        this.graph.addVertex(T.label, "Person", "name", "marko");
        this.graph.tx().commit();
        assertEquals("marko", g.V().has(T.label, "Person").has("name", "marko").next().value("name"));
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
neo4j-gremlin/src/test/java/org/apache/tinkerpop/gremlin/neo4j/structure/NativeNeo4jIndexCheck.java