openstack/oslo.db
Code Issues Proposed changes

Make DBAPI class work with mocks correctly

Browse Source 
Currently, DBAPI __getattr__() implementation will *always*
implicitly wrap all mocked methods of a target class/module using
wrap_db_retry(), as retry_on_* attributes will always exist and be
true for mock instances. Not only this leads to a situation, when
we would retry methods, we were not going to retry, but this also
fails with AttributeError on functools.wraps() call, breaking valid
unit tests in projects.

DBAPI is changed in a way, so that it does dict look ups instead of
fetching instance attributes to ensure mocked methods are handled
correctly and aren't wrapped when they shouldn't be wrapped.

Related issue:
http://stackoverflow.com/questions/22204660/python-mock-wrapsf-problems

Change-Id: I36550ffa88056c53a431d64e61e84fbb44bbf68d
This commit is contained in:
Roman Podoliaka 2015-02-25 15:38:50 +02:00
parent 96cabf40ba
commit 7bfdb6a704
2 changed files with 16 additions and 7 deletions
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15
oslo_db/api.py
View File

@ -56,7 +56,7 @@ def safe_for_db_retry(f):
:param f: database api method. :param f: database api method.
:type f: function. :type f: function.
""" """
f.enable_retry_on_disconnect = True f.__dict__['enable_retry_on_disconnect'] = True
return f return f
@ -66,7 +66,7 @@ def retry_on_deadlock(f):
wrap_db_entry will be applied to all db.api functions marked with this wrap_db_entry will be applied to all db.api functions marked with this
decorator. decorator.
""" """
f.enable_retry_on_deadlock = True f.__dict__['enable_retry_on_deadlock'] = True
return f return f
@ -76,7 +76,7 @@ def retry_on_request(f):
wrap_db_entry will be applied to all db.api functions marked with this wrap_db_entry will be applied to all db.api functions marked with this
decorator. decorator.
""" """
f.enable_retry_on_request = True f.__dict__['enable_retry_on_request'] = True
return f return f
@ -225,10 +225,11 @@ class DBAPI(object):
# NOTE(vsergeyev): If `use_db_reconnect` option is set to True, retry # NOTE(vsergeyev): If `use_db_reconnect` option is set to True, retry
# DB API methods, decorated with @safe_for_db_retry # DB API methods, decorated with @safe_for_db_retry
# on disconnect. # on disconnect.
retry_on_disconnect = self.use_db_reconnect and getattr( retry_on_disconnect = self.use_db_reconnect and attr.__dict__.get(
attr, 'enable_retry_on_disconnect', False) 'enable_retry_on_disconnect', False)
retry_on_deadlock = getattr(attr, 'enable_retry_on_deadlock', False) retry_on_deadlock = attr.__dict__.get('enable_retry_on_deadlock',
retry_on_request = getattr(attr, 'enable_retry_on_request', False) False)
retry_on_request = attr.__dict__.get('enable_retry_on_request', False)
if retry_on_disconnect or retry_on_deadlock or retry_on_request: if retry_on_disconnect or retry_on_deadlock or retry_on_request:
attr = wrap_db_retry( attr = wrap_db_retry(

8
oslo_db/tests/test_api.py
View File

@ -196,3 +196,11 @@ class DBRetryRequestCase(DBAPITestCase):
res = {'result': 0} res = {'result': 0}
self.assertRaises(ValueError, some_method, res) self.assertRaises(ValueError, some_method, res)
self.assertEqual(max_retries + 1, res['result']) self.assertEqual(max_retries + 1, res['result'])
@mock.patch.object(DBAPI, 'api_class_call1')
@mock.patch.object(api, 'wrap_db_retry')
def test_mocked_methods_are_not_wrapped(self, mocked_wrap, mocked_method):
dbapi = api.DBAPI('oslo_db.tests.test_api')
dbapi.api_class_call1()
self.assertFalse(mocked_wrap.called)