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.  | 
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| .. | ||
| approx.py | ||
| collect.py | ||
| fixtures.py | ||
| integration.py | ||
| metafunc.py | ||
| raises.py | ||
| show_fixtures_per_test.py | ||