pytest-monkeyplus - monkeypatch with extras
The monkeyplus plugin is a funcarg that subclasses monkeypatch and adds a few extra features to it.
monkeyplus has three extra methods: patch_osstat, patch_today and patch_time_ticking.
Patching os.stat is tricky because you usually want to patch only one file, not the whole filesystem. Moreover, to patch it properly, you have to return a full stat_result structure. patch_osstat takes care of this stuff. Just call it with a path to patch and keyword arguments for the stat attributes you want, for example:
Arguments that are not specified will be assigned a default value.
patch_today(year, month, day)
Patching dates can be tricky because there's a couple of time relates modules, namely datetime and time. If you want your patch to affect the whole app uniformly, you have to patch the time module, not the datetime module. The arithmetics to transform a year/month/day value in a suitable time.time value are non-trivial, so it can get boring to repeat. Call patch_today with the date you'd like the app to be patched to, example:
monkeyplus.patch_today(2011, 2, 16)
This monkeypatch ensures that all time.time() calls yield different results (and increasing). On many platforms, this is already guaranteed, but not on all of them.
If force_int_diff is True, the patch ensures that all int(time.time()) calls yield different results. Note that it also means that the patches function will return int values.
monkeyplus is a subclass of monkeypatch, so it can be used everywhere monkeypatch is used. Instead of having to use a different funcarg, you can replace monkeypatch by putting this in your conftest.py file:
def pytest_funcarg__monkeypatch(request): monkeyplus = request.getfuncargvalue('monkeyplus') return monkeyplus
For now, monkeyplus is a plugin that reflect my own needs, but if you'd like to contribute new features to it, they're welcome. The source is hosted at http://bitbucket.org/hsoft/pytest-monkeyplus