Public bug reported: Description ===========
In typical unit tests, almost all of the dependencies are mocked or patched (mock.patch), without any guarantee that the mocked methods actually exist, or if their signatures are respected (see below). Because of this, actual issues can easily be overlooked and missed, as the unit tests are wrongfully passing. [0] The mock.Mock class accepts a spec as an argument, which only solves half the problem: it only checks if an attribute exists, based on the given spec. It does not guarantee that the given attribute is actually a method, or if its signature is respected [1][2]. Some unit tests may pass the autospec argument, but mock doesn't support it at the moment. mock.patch, mock.patch.object, mock.patch.multiple accept an autospec argument, but because of a bug [3][4], it cannot be used properly. Steps to reproduce ================== import mock from mock.tests import testmock m = mock.Mock(spec=testmock.Something) # meth has the following signature: # def meth(self, a, b, c, d=None): m.meth() Expected result =============== TypeError should be raised. Actual result ============= A mock object is returned. Proposal ======== Bug reports have been issues for the bugs mentioned above, see [1][2][3][4], but until then, the mock library can be patched to include the following changes: - add autospec argument to mock.Mock and mock.MagicMock. Unit test should then pass the autospec argument whenever possible. - fix the mock.patch autospec issue. - enable mock.patch autospec by default, unless otherwise specified. Links ===== [0] https://review.openstack.org/#/c/461689/ [1] https://github.com/testing-cabal/mock/issues/393 [2] https://bugs.python.org/issue30587 [3] https://github.com/testing-cabal/mock/issues/396 [4] https://bugs.python.org/issue32092 ** Affects: networking-hyperv Importance: Undecided Assignee: Claudiu Belu (cbelu) Status: New ** Affects: nova Importance: Undecided Assignee: Claudiu Belu (cbelu) Status: New ** Affects: os-win Importance: Undecided Assignee: Claudiu Belu (cbelu) Status: New ** Affects: oslotest Importance: Undecided Assignee: Claudiu Belu (cbelu) Status: In Progress ** Tags: testing ** Also affects: oslotest Importance: Undecided Status: New ** Also affects: os-win Importance: Undecided Status: New ** Also affects: networking-hyperv Importance: Undecided Status: New ** Changed in: nova Assignee: (unassigned) => Claudiu Belu (cbelu) ** Changed in: networking-hyperv Assignee: (unassigned) => Claudiu Belu (cbelu) ** Changed in: os-win Assignee: (unassigned) => Claudiu Belu (cbelu) ** Changed in: oslotest Assignee: (unassigned) => Claudiu Belu (cbelu) -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to OpenStack Compute (nova). https://bugs.launchpad.net/bugs/1735588 Title: Mock autospec not used, or not used properly Status in networking-hyperv: New Status in OpenStack Compute (nova): New Status in os-win: New Status in oslotest: In Progress Bug description: Description =========== In typical unit tests, almost all of the dependencies are mocked or patched (mock.patch), without any guarantee that the mocked methods actually exist, or if their signatures are respected (see below). Because of this, actual issues can easily be overlooked and missed, as the unit tests are wrongfully passing. [0] The mock.Mock class accepts a spec as an argument, which only solves half the problem: it only checks if an attribute exists, based on the given spec. It does not guarantee that the given attribute is actually a method, or if its signature is respected [1][2]. Some unit tests may pass the autospec argument, but mock doesn't support it at the moment. mock.patch, mock.patch.object, mock.patch.multiple accept an autospec argument, but because of a bug [3][4], it cannot be used properly. Steps to reproduce ================== import mock from mock.tests import testmock m = mock.Mock(spec=testmock.Something) # meth has the following signature: # def meth(self, a, b, c, d=None): m.meth() Expected result =============== TypeError should be raised. Actual result ============= A mock object is returned. Proposal ======== Bug reports have been issues for the bugs mentioned above, see [1][2][3][4], but until then, the mock library can be patched to include the following changes: - add autospec argument to mock.Mock and mock.MagicMock. Unit test should then pass the autospec argument whenever possible. - fix the mock.patch autospec issue. - enable mock.patch autospec by default, unless otherwise specified. Links ===== [0] https://review.openstack.org/#/c/461689/ [1] https://github.com/testing-cabal/mock/issues/393 [2] https://bugs.python.org/issue30587 [3] https://github.com/testing-cabal/mock/issues/396 [4] https://bugs.python.org/issue32092 To manage notifications about this bug go to: https://bugs.launchpad.net/networking-hyperv/+bug/1735588/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : [email protected] Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp
