In pytester tests, pytest stashes & restores the sys.modules for each
test. So if the test imports a new module, it is initialized anew each
time.
Turns out the readline module isn't multi-init safe, which causes
pytester.spawn to crash or hang. So preserve it as a workaround.
This indicates at least for people using type checkers that these
classes are not designed for inheritance and we make no stability
guarantees regarding inheritance of them.
Currently this doesn't show up in the docs. Sphinx does actually support
`@final`, however it only works when imported directly from `typing`,
while we import from `_pytest.compat`.
In the future there might also be a `@sealed` decorator which would
cover some more cases.
This option checks even functions which are not annotated. It's a good
step to ensure that existing type annotation are correct.
In a Pareto fashion, the last few holdouts are always the ugliest,
beware.
_pytest.timing is an indirection to 'time' functions, which pytest production
code should use instead of 'time' directly.
'mock_timing' is a new fixture which then mocks those functions, allowing us
to write time-reliable tests which run instantly and are not flaky.
This was triggered by recent flaky junitxml tests on Windows related to timing
issues.
When using `(i)var` in the class docstring it would link `duration` to
`_pytest.runner.TestReport.duration`.
This moves the docstrings to the attributes properly.
ExitCode is used in several internal modules and hooks and so with type
annotations added, needs to be imported a lot.
_pytest.main, being the entry point, generally sits at the top of the
import tree.
So, it's not great to have ExitCode defined in _pytest.main, because it
will cause a lot of import cycles once type annotations are added (in
fact there is already one, which this change removes).
Move it to _pytest.config instead.
_pytest.main still imports ExitCode, so importing from there still
works, although external users should really be importing from `pytest`.
