JS: Add unit tests (with coverage) & use `URL` object instead of strings to construct some URLs

yuvipanda commented 1 year ago

Re-adds https://github.com/jupyterhub/binderhub/pull/1741, but with Jest based unit tests. Jest seems fairly popular and is also what JupyterLab & JupyterHub admin uses, so it feels appropriate here.
Adds a small unit test for the binderhub frontend too (for updateFavicon), so we can slowly add more tests there. This actually helped catch a bug in updateFavicon - we were unconditionally appending <link> tags to <head>, so the number of tags grew each time the icon changed. There is now a unit test to catch this.
Use typed URL objects to construct build URLs, rather than just doing string concatenation. I'll try to slowly move all URL manipulation to using URL object
Use typed URL objects to construct the URL we eventually redirect users to, and add unit tests. Some cleanup here to make this actually unit testable rather than test side effects (window.location)
Uploads JS test coverage stats to codecov as well, so we can track and improve our JS coverage
Remove implicit dependency of binderhub-client on jquery for URL parameter manipulation.
This still isn't enough to actually fully catch the issues of 1741 yet, so here's a screen recording of me testing it via the UI (this includes the changes in #1761 as well)

yuvipanda commented 1 year ago

The test failures seem unrelated

yuvipanda commented 1 year ago

JS tests are running here again, and looks like the failures are unrelated

yuvipanda commented 1 year ago

Yep, given the same tests are failing for https://github.com/jupyterhub/binderhub/pull/1766 as well, I'm pretty sure they're unrelated.

consideRatio commented 1 year ago

+1 to disregard the test failure atm.

I think its good if the title reflects that its more than added tests in this PR though, and a label is added as well.

yuvipanda commented 1 year ago

@consideRatio good call! I've updated the title and added some labels.

jupyterhub / binderhub