Upgrading pytest causes TypeError: 'NoneType' object is not callable error

Question

需要帮助升级 pytest。在 3.2.4 上，如果我移动到 3.3.x 或 3.4.x，我会收到一个我不理解的错误，我什至无法执行 -h 参数。不知道从哪里开始或为什么会这样。也许我的 virtualenv 有问题？

新鲜的虚拟环境

我确实尝试从全新的 virtualenv 开始，但是，我仍然遇到同样的错误。恢复到 3.2.4 修复它。

工作：

$ pytest --version
This is pytest version 3.2.4, imported from /Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pytest.py

升级到 3.3.x

$ pytest --version
This is pytest version 3.3.2, imported from /Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pytest.py

$ pytest --help
Traceback (most recent call last):
  File "/Users/me/.virtualenvs/hitcount/bin/pytest", line 11, in <module>
    sys.exit(main())
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/_pytest/config.py", line 59, in main
    return config.hook.pytest_cmdline_main(config=config)
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/__init__.py", line 617, in __call__
    return self._hookexec(self, self._nonwrappers + self._wrappers, kwargs)
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/__init__.py", line 222, in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/__init__.py", line 216, in <lambda>
    firstresult=hook.spec_opts.get('firstresult'),
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/callers.py", line 201, in _multicall
    return outcome.get_result()
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/callers.py", line 76, in get_result
    raise ex[1].with_traceback(ex[2])
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/callers.py", line 180, in _multicall
    res = hook_impl.function(*args)
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/_pytest/helpconfig.py", line 102, in pytest_cmdline_main
    config._do_configure()
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/_pytest/config.py", line 921, in _do_configure
    self.hook.pytest_configure.call_historic(kwargs=dict(config=self))
  File "/Users/me/.virtualenvs/hitcount/lib/python3.5/site-packages/pluggy/__init__.py", line 630, in call_historic
    proc(x)
TypeError: 'NoneType' object is not callable

来源：

这是我维护的一个开源项目：https://github.com/thornomad/django-hitcount

Answer 1

您遇到的错误不在 pytest 中，而是在它所基于的插件库中，pluggy。该错误已在 2 个月前修复 (see this commit)，但不幸的是，当前最新版本 pluggy (0.6.0) 不包含此修复。

因此你有两种可能性：

取决于`pluggy`快照

这是侵入性最小的一种。 pytest 不需要 pluggy 的严格版本，所以只需要开发版本直到下一个 pluggy 发布：

# tests/requirements.txt

coverage==4.5.1
flake8==2.5.4
mock==2.0.0
pytest==3.4.2
pytest-django==3.1.2
selenium==3.10.0
tox==2.9.1
# add some meaningful explanation here 
# so you don't forget why you need this particular snapshot of pluggy
git+https://github.com/pytest-dev/pluggy@dcde058f93a509b9c39409fca02100e43bb43485

下个版本发布后，移除snapshot依赖和bump:

pluggy>0.6.0

适配`pytest_configure`挂钩

调整您的 pytest_configure 挂钩，使其不 return 任何东西：

def configure():
    from django.conf import settings

    settings.configure(
        ...

    return settings

def pytest_configure():
    configure()

不要忘记在 runtests.py 中调用 configure() 函数而不是 pytest_configure()，这样就可以了。但是，这只是一种临时解决方法，可以在 pluggy>0.6.0 发布后恢复。

Answer 2

通过将pytest升级到4.0.1，可以解决这个问题。最新版pytest >5.1 不兼容 python >3.4.

Upgrading pytest causes TypeError: 'NoneType' object is not callable error