Fixtures 2.0 is overly strict on monkeypatch requirements

[Andrew Laski]

Fixtures 2.0 added some better handling of staticmethods in MonkeyPatch, but unintentionally caused a constraint that bound methods of a class be patched with similarly bound methods of that class. This is due to checking the wrong attribute for staticness when doing the patching. As a result workarounds like the following are required:

diff --git a/nova/tests/fixtures.py b/nova/tests/fixtures.py
index 58ef19e..f72e4e6 100644
--- a/nova/tests/fixtures.py
+++ b/nova/tests/fixtures.py
@@ -584,14 +584,19 @@ class StableObjectJsonFixture(fixtures.Fixture):
     def setUp(self):
         super(StableObjectJsonFixture, self).setUp()

- def _doit(obj, *args, **kwargs):
+ def _obj_to_prim_sorter(obj, *args, **kwargs):
             result = self._original_otp(obj, *args, **kwargs)
             if 'nova_object.changes' in result:
                 result['nova_object.changes'].sort()
             return result

+ # NOTE(alaski): This makes _obj_to_prim_sorter into an instancemethod
+ # so that its signature matches the method it's patching
+ obj_base.NovaObject._obj_to_prim_sorter = _obj_to_prim_sorter
+
         self.useFixture(fixtures.MonkeyPatch(
- 'nova.objects.base.NovaObject.obj_to_primitive', _doit))
+ 'nova.objects.base.NovaObject.obj_to_primitive',
+ obj_base.NovaObject._obj_to_prim_sorter))

 class EngineFacadeFixture(fixtures.Fixture):

I don't think it's desirable that the requirements be that strict.

[Andrew Laski (alaski)]

https://github.com/testing-cabal/fixtures/pull/26

[Robert Collins (lifeless)]

We're discussing on the pull request, but trivial examples still work for me - so ECONFUSED.

[Robert Collins (lifeless)]

Fixed in 3.0.0.