### Question:
ExtResourceTransactionManager implements TransactionManager, Serializable { @Override public void commit(UUID transactionId) { this.getBusinessObject(transactionId).commit(transactionId); this.internalTransactionManager.commit(transactionId); } ExtResourceTransactionManager(
            SandboxProvider sandboxProvider, TransactionManager internalTransactionManager); @Override void join(UUID transactionId); @Override void leave(UUID transactionId); @Override Vote vote(UUID transactionId); @Override void commit(UUID transactionId); @Override void abort(UUID transactionId);  }### Answer:
@Test public void test_tx_primitive_engages_intTxMgr_and_extResource() { txMgr.commit(transcationId); verify(intTxManager, times(1)).commit(transcationId); verify(businessObject, times(1)).commit(transcationId); }