@Test public void graphDSG_view_txn_3() {

    DatasetGraph dsg = DatasetGraphFactory.createTxnMem();
    Graph graph = dsg.getDefaultGraph();
    Triple triple = SSE.parseTriple("(<s> <p> 0)") ;
    assertFalse(graph.contains(triple));
    graph.getTransactionHandler().execute(()->graph.add(triple) );
    graph.getTransactionHandler().execute(()->assertTrue(graph.contains(triple)) );
}