tests: Port unit tests to jasmine
The jsUnit module included with gjs is very basic, and has been considered deprecated for many years.
Jasmine is a popular testing framework for javascript, with the jasmine-gjs project providing support for gjs.
gjs itself uses jasmine for its unit tests (albeit with a minimal embedded jasmine runner instead of jasmine-gjs).
That is, there are good reason to switch to jasmine for our own unit tests:
- maintained
- more structured and expressive tests
- same framework as gjs
There was an old attempt many years ago (pre-meson, pre-ESM, pre-half-our-unit-tests), pick that up to really make it happen this time.