Make "py.test --help" more friendly if DSM is set, but PYTHONPATH is not

[blueyed]

pytest-django might cause py.test --help to behave very unfriendly, when
DJANGO_SETTINGS_MODULE is set, but PYTHONPATH is not set correctly. See the traceback below.

It would be nice if it would behave better, especially when py.test --help is used.

% py.test --help
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
…/django17/django/conf/__init__.py in __init__(self, settings_module)
     93         try:
---> 94             mod = importlib.import_module(self.SETTINGS_MODULE)
     95         except ImportError as e:

…/pyenv/project/lib/python3.4/importlib/__init__.py in import_module(name, package)
    108             level += 1
--> 109     return _bootstrap._gcd_import(name[level:], package, level)
    110 

…/pyenv/project/lib/python3.4/importlib/_bootstrap.py in _gcd_import(name, package, level)

…/pyenv/project/lib/python3.4/importlib/_bootstrap.py in _find_and_load(name, import_)

…/pyenv/project/lib/python3.4/importlib/_bootstrap.py in _find_and_load_unlocked(name, import_)

…/pyenv/project/lib/python3.4/importlib/_bootstrap.py in _call_with_frames_removed(f, *args, **kwds)

…/pyenv/project/lib/python3.4/importlib/_bootstrap.py in _gcd_import(name, package, level)

…/pyenv/project/lib/python3.4/importlib/_bootstrap.py in _find_and_load(name, import_)

…/pyenv/project/lib/python3.4/importlib/_bootstrap.py in _find_and_load_unlocked(name, import_)

ImportError: No module named 'config'

During handling of the above exception, another exception occurred:

ImportError                               Traceback (most recent call last)
…/pytest-django/pytest_django/plugin.py in _handle_import_error(extra_message)
     91     try:
---> 92         yield
     93     except ImportError as e:

…/pytest-django/pytest_django/plugin.py in pytest_load_initial_conftests(early_config, parser, args)
    197         with _handle_import_error(_django_project_scan_outcome):
--> 198             settings.DATABASES
    199 

…/django17/django/conf/__init__.py in __getattr__(self, name)
     45         if self._wrapped is empty:
---> 46             self._setup(name)
     47         return getattr(self._wrapped, name)

…/django17/django/conf/__init__.py in _setup(self, name)
     41 
---> 42         self._wrapped = Settings(settings_module)
     43 

…/django17/django/conf/__init__.py in __init__(self, settings_module)
     97                 "Could not import settings '%s' (Is it on sys.path? Is there an import error in the settings file?): %s"
---> 98                 % (self.SETTINGS_MODULE, e)
     99             )

ImportError: Could not import settings 'config.settings' (Is it on sys.path? Is there an import error in the settings file?): No module named 'config'

During handling of the above exception, another exception occurred:

ImportError                               Traceback (most recent call last)
…/pyenv/project/bin/py.test in <module>()
      9 if __name__ == '__main__':
     10     sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
---> 11     sys.exit(main())

…/pyenv/project/lib/python3.4/site-packages/_pytest/config.py in main(args, plugins)
     30     """
     31     try:
---> 32         config = _prepareconfig(args, plugins)
     33     except ConftestImportFailure:
     34         e = sys.exc_info()[1]

…/pyenv/project/lib/python3.4/site-packages/_pytest/config.py in _prepareconfig(args, plugins)
     83                 pluginmanager.register(plugin)
     84         return pluginmanager.hook.pytest_cmdline_parse(
---> 85                 pluginmanager=pluginmanager, args=args)
     86     except Exception:
     87         pluginmanager.ensure_shutdown()

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in __call__(self, **kwargs)
    519 
    520     def __call__(self, **kwargs):
--> 521         return self._docall(self.methods, kwargs)
    522 
    523     def callextra(self, methods, **kwargs):

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in _docall(self, methods, kwargs)
    526     def _docall(self, methods, kwargs):
    527         return MultiCall(methods, kwargs,
--> 528                          firstresult=self.firstresult).execute()
    529 
    530 

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in execute(self)
    391             args = [all_kwargs[argname] for argname in varnames(method)]
    392             if hasattr(method, "hookwrapper"):
--> 393                 return wrapped_call(method(*args), self.execute)
    394             res = method(*args)
    395             if res is not None:

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in wrapped_call(wrap_controller, func)
    107     call_outcome = CallOutcome(func)
    108     try:
--> 109         wrap_controller.send(call_outcome)
    110         raise_wrapfail(wrap_controller, "has second yield")
    111     except StopIteration:

…/pyenv/project/lib/python3.4/site-packages/_pytest/helpconfig.py in pytest_cmdline_parse()
     26 def pytest_cmdline_parse():
     27     outcome = yield
---> 28     config = outcome.get_result()
     29     if config.option.debug:
     30         path = os.path.abspath("pytestdebug.log")

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in get_result(self)
    135             ex = self.excinfo
    136             if py3:
--> 137                 raise ex[1].with_traceback(ex[2])
    138             py.builtin._reraise(*ex)
    139 

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in __init__(self, func)
    121     def __init__(self, func):
    122         try:
--> 123             self.result = func()
    124         except Exception:
    125             self.excinfo = sys.exc_info()

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in execute(self)
    392             if hasattr(method, "hookwrapper"):
    393                 return wrapped_call(method(*args), self.execute)
--> 394             res = method(*args)
    395             if res is not None:
    396                 self.results.append(res)

…/pyenv/project/lib/python3.4/site-packages/_pytest/config.py in pytest_cmdline_parse(self, pluginmanager, args)
    634     def pytest_cmdline_parse(self, pluginmanager, args):
    635         assert self == pluginmanager.config, (self, pluginmanager.config)
--> 636         self.parse(args)
    637         return self
    638 

…/pyenv/project/lib/python3.4/site-packages/_pytest/config.py in parse(self, args)
    744                 "can only parse cmdline args at most once per Config object")
    745         self._origargs = args
--> 746         self._preparse(args)
    747         # XXX deprecated hook:
    748         self.hook.pytest_cmdline_preparse(config=self, args=args)

…/pyenv/project/lib/python3.4/site-packages/_pytest/config.py in _preparse(self, args, addopts)
    716         try:
    717             self.hook.pytest_load_initial_conftests(early_config=self,
--> 718                     args=args, parser=self._parser)
    719         except ConftestImportFailure:
    720             e = sys.exc_info()[1]

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in __call__(self, **kwargs)
    519 
    520     def __call__(self, **kwargs):
--> 521         return self._docall(self.methods, kwargs)
    522 
    523     def callextra(self, methods, **kwargs):

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in _docall(self, methods, kwargs)
    526     def _docall(self, methods, kwargs):
    527         return MultiCall(methods, kwargs,
--> 528                          firstresult=self.firstresult).execute()
    529 
    530 

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in execute(self)
    391             args = [all_kwargs[argname] for argname in varnames(method)]
    392             if hasattr(method, "hookwrapper"):
--> 393                 return wrapped_call(method(*args), self.execute)
    394             res = method(*args)
    395             if res is not None:

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in wrapped_call(wrap_controller, func)
    111     except StopIteration:
    112         pass
--> 113     return call_outcome.get_result()
    114 
    115 

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in get_result(self)
    135             ex = self.excinfo
    136             if py3:
--> 137                 raise ex[1].with_traceback(ex[2])
    138             py.builtin._reraise(*ex)
    139 

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in __init__(self, func)
    121     def __init__(self, func):
    122         try:
--> 123             self.result = func()
    124         except Exception:
    125             self.excinfo = sys.exc_info()

…/pyenv/project/lib/python3.4/site-packages/_pytest/core.py in execute(self)
    392             if hasattr(method, "hookwrapper"):
    393                 return wrapped_call(method(*args), self.execute)
--> 394             res = method(*args)
    395             if res is not None:
    396                 self.results.append(res)

…/pytest-django/pytest_django/plugin.py in pytest_load_initial_conftests(early_config, parser, args)
    196 
    197         with _handle_import_error(_django_project_scan_outcome):
--> 198             settings.DATABASES
    199 
    200         _setup_django()

…/pyenv/3.4.3/lib/python3.4/contextlib.py in __exit__(self, type, value, traceback)
     75                 value = type()
     76             try:
---> 77                 self.gen.throw(type, value, traceback)
     78                 raise RuntimeError("generator didn't stop after throw()")
     79             except StopIteration as exc:

…/pytest-django/pytest_django/plugin.py in _handle_import_error(extra_message)
     94         django_msg = (e.args[0] + '\n\n') if e.args else ''
     95         msg = django_msg + extra_message
---> 96         raise ImportError(msg)
     97 
     98 

ImportError: Could not import settings 'config.settings' (Is it on sys.path? Is there an import error in the settings file?): No module named 'config'

pytest-django could not find a Django project (no manage.py file could be found). You must explicitly add your Django project to the Python path to have it picked up.

[hpk42]

I think plugin.py could try to use a autouse session-scoped fixture for setting up django instead of the current pytest_configure hook here https://github.com/pytest-dev/pytest-django/blob/master/pytest_django/plugin.py#L204 . pytest_configure is called before --help is called whereas fixtures are not touched.

[blueyed]

Thanks for looking into this!

It's also being called through pytest_load_initial_conftests though.

I've experimented with moving it from there, too - but it appears a session-scoped autouse fixture is too late, in case you import Django models in your project's conftest.py: Django then complains that models/apps are not ready yet.
(edit I think that we could require a project to call django.setup then manually)

We need to call django.setup() before a project's conftest.py is being loaded/handled, but after --help would be displayed.

I've seen that there's pytest_collectstart, but that's also too late.

Here is the traceback when importing the Django models in the project's conftest.py:

Traceback (most recent call last):
  File "…/pyenv/project/lib/python3.4/site-packages/_pytest/config.py", line 513, in getconftestmodules
    return self._path2confmods[path]
KeyError: local('…/project')

During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "…/pyenv/project/lib/python3.4/site-packages/_pytest/config.py", line 537, in importconftest
    return self._conftestpath2mod[conftestpath]
KeyError: local('…/project/conftest.py')

During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "…/pyenv/project/lib/python3.4/site-packages/_pytest/config.py", line 543, in importconftest
    mod = conftestpath.pyimport()
  File "…/pyenv/project/lib/python3.4/site-packages/py/_path/local.py", line 641, in pyimport
    __import__(modname)
  File "…/project/conftest.py", line 16, in <module>
    from app.factories import ModelFactory, VideoFactory
  File "…/project/app/factories.py", line 27, in <module>
    class VideoFactory(factory.django.DjangoModelFactory):
  File "…/factory_boy/factory/base.py", line 123, in __new__
    base_factory=base_factory,
  File "…/factory_boy/factory/base.py", line 210, in contribute_to_class
    self.model = self.factory._load_model_class(self.model)
  File "…/factory_boy/factory/django.py", line 109, in _load_model_class
    return get_model(app, model)
  File "…/django18/django/apps/registry.py", line 199, in get_model
    self.check_models_ready()
  File "…/django18/django/apps/registry.py", line 131, in check_models_ready
    raise AppRegistryNotReady("Models aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Models aren't loaded yet.
ERROR: could not load …/project/conftest.py