@Test
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_ADD_VERTICES)
    @FeatureRequirement(featureClass = Graph.Features.GraphFeatures.class, feature = Graph.Features.GraphFeatures.FEATURE_TRANSACTIONS)
    @FeatureRequirement(featureClass = Graph.Features.GraphFeatures.class, feature = Graph.Features.GraphFeatures.FEATURE_THREADED_TRANSACTIONS)
    public void shouldOpenTxWhenThreadedTransactionIsCreated() throws Exception {
        // threaded transactions should be immediately open on creation
        final Graph threadedG = g.tx().createThreadedTx();
        assertThat(threadedG.tx().isOpen(), is(true));

        threadedG.tx().rollback();
        assertThat(threadedG.tx().isOpen(), is(false));
    }
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/structure/TransactionTest.java