@Test
public void rollback() {

    XOTransaction xoTransaction = new XOTransactionImpl(datastoreTransaction);
    xoTransaction.begin();
    assertThat(xoTransaction.isActive(), equalTo(true));
    xoTransaction.rollback();
    assertThat(xoTransaction.isActive(), equalTo(false));
    verify(datastoreTransaction).begin();
    verify(datastoreTransaction, never()).commit();
    verify(datastoreTransaction).rollback();
    verify(datastoreTransaction, times(2)).isActive();
}