New review comment by ahesford on void-packages repository

https://github.com/void-linux/void-packages/pull/44268#discussion_r1218208379

Comment:
The problem isn't that this works in a `venv`, it's how you're calling `pytest`. The default `do_build` runs `pytest3` but you are running `python3 -m pytest`, which means you add `.` to the Python path by default. If you were to run
```sh
ln -Tsf /usr/bin/pytest3 "${testdir}/bin/pytest3"
"${testdir}/bin/pytest3"
```
instead of `python3 -m pytest`, the tests would again fail with an inability to find `IPython`.

This suggests that `pytest` is not actually testing against the contents of the wheel, but is instead testing the contents of the source tree. (Although, in the single test `test_ipython_embed`, it expects to find an `ipython` entrypoint and fails.) In fact, it is sufficient to do
```sh
do_check() {
    python3 -m pytest -k 'not(test_ipython_embed)'
}
```
for a successful test run.