当我尝试保存具有相同id的对象时，mongoengine中的唯一索引约束会引发此异常：
|2018-06-28 14:23:28.084| [DEBUG] (rec.exchange.base|26): Processing exchange data
Traceback (most recent call last):
File "/home/nst/virtualenvs/myenv/lib/python3.6/site-packages/mongoengine/document.py", line 372, in save
object_id = self._save_create(doc, force_insert, write_concern)
File "/home/nst/virtualenvs/myenv/lib/python3.6/site-packages/mongoengine/document.py", line 428, in _save_create
object_id = collection.save(doc, **write_concern)
File "/home/nst/virtualenvs/myenv/lib/python3.6/site-packages/pymongo/collection.py", line 2917, in save
to_save, True, check_keys, manipulate, write_concern)
File "/home/nst/virtualenvs/myenv/lib/python3.6/site-packages/pymongo/collection.py", line 599, in _insert
bypass_doc_val, session)
File "/home/nst/virtualenvs/myenv/lib/python3.6/site-packages/pymongo/collection.py", line 580, in _insert_one
_check_write_command_response(result)
File "/home/nst/virtualenvs/myenv/lib/python3.6/site-packages/pymongo/helpers.py", line 207, in _check_write_command_response
_raise_last_write_error(write_errors)
File "/home/nst/virtualenvs/myenv/lib/python3.6/site-packages/pymongo/helpers.py", line 188, in _raise_last_write_error
raise DuplicateKeyError(error.get("errmsg"), 11000, error)
pymongo.errors.DuplicateKeyError: E11000 duplicate key error collection: TRX.exchanges index: exchange_1_order.id_1 dup key: { : "BFNX", : "1234" }
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "run.py", line 5, in <module>
application.run()
File "/home/nst/Dev/rec/rec/trx_app.py", line 118, in run
self.run_scheduler_app()
File "/home/nst/Dev/rec/rec/trx_app.py", line 106, in run_scheduler_app
self.run_jobs_hook_without_scheduler()
File "/home/nst/Dev/rec/rec/trx_app.py", line 92, in run_jobs_hook_without_scheduler
get_exchange_job(order)
File "/home/nst/Dev/rec/rec/scheduler/job_hooks.py", line 39, in get_exchange_job
ExchangeJob(job_cfg).run()
File "/home/nst/Dev/rec/rec/exchange/job.py", line 22, in run
exchange_data = self.data_source.get_exchange_data()
File "/home/nst/Dev/rec/rec/exchange/base.py", line 15, in get_exchange_data
return self._map_data(self._read_data())
File "/home/nst/Dev/rec/rec/exchange/base.py", line 31, in _read_data
parser = self._build_data_parser()
File "/home/nst/Dev/rec/rec/exchange/impl/bitfinex.py", line 113, in _build_data_parser
ed1.save()
File "/home/nst/virtualenvs/myenv/lib/python3.6/site-packages/mongoengine/document.py", line 395, in save
raise NotUniqueError(message % six.text_type(err))
mongoengine.errors.NotUniqueError: Tried to save duplicate unique keys (E11000 duplicate key error collection: TRX.exchanges index: exchange_1_order.id_1 dup key: { : "BFNX", : "1234" })
我正在尝试为这种情况编写单元测试：
from mongoengine.errors import NotUniqueError
def test_duplicate_exchange_data(self):
order1 = ExchangeOrder(id='1234', currency_pair='tBTGUSD',
datetime=datetime.datetime.today(),
amount=1500, price=57)
exchange_data1 = ExchangeData(exchange='BFNX', order=order1)
exchange_data1.save()
order2 = ExchangeOrder(id='1234', currency_pair='tBTCUSD',
datetime=datetime.datetime.today(),
amount=500, price=57.5)
exchange_data2 = ExchangeData(exchange='BFNX', order=order2)
self.assertRaises(NotUniqueError, exchange_data2.save)
但是assertRaises()由于第二个异常而无法正常工作。在测试中如何处理？