### Question:
JCoTransaction extends AbstractTransaction { public void begin() { if (inTransaction) { throw new HibersapException("Transaction was already started"); } inTransaction = true; } JCoTransaction(final SessionImplementor session); void begin(); void commit(); void rollback();  }### Answer:
@Test(expected = HibersapException.class) public void testMustNotBeginAlreadyStartedTransaction() { transaction.begin(); transaction.begin(); }