Source was previously iterable because it implements `__getitem__()`,
which is apparently a thing from before `__iter__()` was introduced.
To reduce mypy's and my own confusion, implement `__iter__()` directly.
The previous test was better in that it used fakes to test all of the
real code paths. The problem with that is that it makes it impossible to
simplify the code with `isinstance` checks. So let's just simulate the
issue directly with a monkeypatch.
Add some Python 3.8 type: ignores; all are already fixed in the next
mypy release, so can be removed once we upgrade.
Also move some flake8 ignores which seem to have changed places.
Instead of giving an example of using sys and then, at the end,
advising not to use sys, just give a correct example. This is
especially helpful since mypy 0.740 has started (correctly) complaining
about sys._called_from_pytest not being present.
It currently fails with a TypeError, and was not updated since 2013 -
therefore it can be assumed that it is not important to support it.
```
____________________ ERROR collecting test_nested_marks.py _____________________
…/Vcs/pluggy/src/pluggy/hooks.py:286: in __call__
return self._hookexec(self, self.get_hookimpls(), kwargs)
…/Vcs/pluggy/src/pluggy/manager.py:93: in _hookexec
return self._inner_hookexec(hook, methods, kwargs)
…/Vcs/pluggy/src/pluggy/manager.py:337: in traced_hookexec
return outcome.get_result()
…/Vcs/pluggy/src/pluggy/manager.py:335: in <lambda>
outcome = _Result.from_call(lambda: oldcall(hook, hook_impls, kwargs))
…/Vcs/pluggy/src/pluggy/manager.py:87: in <lambda>
firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
…/Vcs/pytest/src/_pytest/python.py:235: in pytest_pycollect_makeitem
res = list(collector._genfunctions(name, obj))
…/Vcs/pytest/src/_pytest/python.py:404: in _genfunctions
self.ihook.pytest_generate_tests.call_extra(methods, dict(metafunc=metafunc))
…/Vcs/pluggy/src/pluggy/hooks.py:324: in call_extra
return self(**kwargs)
…/Vcs/pluggy/src/pluggy/hooks.py:286: in __call__
return self._hookexec(self, self.get_hookimpls(), kwargs)
…/Vcs/pluggy/src/pluggy/manager.py:93: in _hookexec
return self._inner_hookexec(hook, methods, kwargs)
…/Vcs/pluggy/src/pluggy/manager.py:337: in traced_hookexec
return outcome.get_result()
…/Vcs/pluggy/src/pluggy/manager.py:335: in <lambda>
outcome = _Result.from_call(lambda: oldcall(hook, hook_impls, kwargs))
…/Vcs/pluggy/src/pluggy/manager.py:87: in <lambda>
firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
…/Vcs/pytest/src/_pytest/python.py:130: in pytest_generate_tests
metafunc.parametrize(*marker.args, **marker.kwargs)
…/Vcs/pytest/src/_pytest/python.py:965: in parametrize
function_definition=self.definition,
…/Vcs/pytest/src/_pytest/mark/structures.py:111: in _for_parametrize
if len(param.values) != len(argnames):
E TypeError: object of type 'MarkDecorator' has no len()
!!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!
```