Using [pytest-xprocess](https://pytest-xprocess.readthedocs.io/) proved
not being as useful as I thought at first, because it was causing
intermitent failures when starting the process.
The code now directly uses `subprocess.popen` calls to start the server.
The tests are grouped together using the following decorator:
`@pytest.mark.xdist_group(name="websockets")`
Tests now need to be run with the `pytest --dist loadgroup` so that all
tests of the same group happen on the same process.
More details on this blogpost:
https://blog.notmyidea.org/start-a-process-when-using-pytest-xdist.html
Those icons would need more love to better factorize the way
they are used:
- the size of the HTML element including the icon is not consistent
- some icons are on the default file but could be in the white one
To be done in a later step
As far as I understand, it default to `let` in these cases because the tool cannot figure out if a `const` is possible. It has to be checked manually:
```
./node_modules/lebab/bin/index.js --replace "umap/static/umap/js/*.js" --transform let
umap/static/umap/js/umap.xhr.js:
228: warning Unable to transform var (let)
umap/static/umap/js/umap.ui.js:
83: warning Unable to transform var (let)
umap/static/umap/js/umap.slideshow.js:
15: warning Unable to transform var (let)
83: warning Unable to transform var (let)
umap/static/umap/js/umap.popup.js:
100: warning Unable to transform var (let)
umap/static/umap/js/umap.permissions.js:
14: warning Unable to transform var (let)
umap/static/umap/js/umap.layer.js:
195: warning Unable to transform var (let)
436: warning Unable to transform var (let)
568: warning Unable to transform var (let)
584: warning Unable to transform var (let)
989: warning Unable to transform var (let)
1088: warning Unable to transform var (let)
1098: warning Unable to transform var (let)
umap/static/umap/js/umap.js:
124: warning Unable to transform var (let)
223: warning Unable to transform var (let)
343: warning Unable to transform var (let)
376: warning Unable to transform var (let)
406: warning Unable to transform var (let)
849: warning Unable to transform var (let)
732: warning Unable to transform var (let)
948: warning Unable to transform var (let)
959: warning Unable to transform var (let)
878: warning Unable to transform var (let)
1085: warning Unable to transform var (let)
umap/static/umap/js/umap.icon.js:
145: warning Unable to transform var (let)
184: warning Unable to transform var (let)
umap/static/umap/js/umap.forms.js:
453: warning Unable to transform var (let)
umap/static/umap/js/umap.features.js:
15: warning Unable to transform var (let)
101: warning Unable to transform var (let)
143: warning Unable to transform var (let)
373: warning Unable to transform var (let)
429: warning Unable to transform var (let)
890: warning Unable to transform var (let)
949: warning Unable to transform var (let)
umap/static/umap/js/umap.core.js:
149: warning Unable to transform var (let)
175: warning Unable to transform var (let)
umap/static/umap/js/umap.controls.js:
665: warning Unable to transform var (let)
876: warning Unable to transform var (let)
1249: warning Unable to transform var (let)
```
