Refs #11662.
--- Problem
Each fixture definition has a "visibility", the `FixtureDef.baseid`
attribute. This is nodeid-like string. When a certain `node` requests a
certain fixture name, we match node's nodeid against the fixture
definitions with this name.
The matching currently happens on the *textual* representation of the
nodeid - we split `node.nodeid` to its "parent nodeids" and then check
if the fixture's `baseid` is in there.
While this has worked so far, we really should try to avoid textual
manipulation of nodeids as much as possible. It has also caused problem
in an odd case of a `Package` in the root directory: the `Package` gets
nodeid `.`, while a `Module` in it gets nodeid `test_module.py`. And
textually, `.` is not a parent of `test_module.py`.
--- Solution
Avoid this entirely by just checking the node hierarchy itself. This is
made possible by the fact that we now have proper `Directory` nodes
(`Dir` or `Package`) for the entire hierarchy.
Also do the same for `_getautousenames` which is a similar deal.
The `iterparentnodeids` function is no longer used and is removed.
Instead of modifying user objects like modules and classes that we
really shouldn't be touching, use the new `_register_fixture` internal
API to do it directly.
Add a function on the `FixtureManager` to register a fixture with
pytest. Currently this can only be done through `parsefactories`.
My aim is to eventually make something like this available to plugins,
as it's a pretty common need.
* Fix handling empty values of NO_COLOR and FORCE_COLOR
Fix handling NO_COLOR and FORCE_COLOR environment variables to correctly
be ignored when they are set to an empty value, as defined
in the specification:
> Command-line software which adds ANSI color to its output by default
> should check for a NO_COLOR environment variable that, when present
> *and not an empty string* (regardless of its value), prevents
> the addition of ANSI color.
(emphasis mine, https://no-color.org/)
The same is true of FORCE_COLOR, https://force-color.org/.
* Streamline testing for FORCE_COLOR and NO_COLOR
Streamline the tests for FORCE_COLOR and NO_COLOR variables, and cover
all possible cases (unset, set to empty, set to "1"). Combine the two
assert functions into one taking boolean parameters. Mock file.isatty
in all circumstances to ensure that the environment variables take
precedence over the fallback value resulting from isatty check (or that
the fallback is actually used, in the case of both FORCE_COLOR
and NO_COLOR being unset).
