That diff aims to test HTML rendering of the contents stored inside the archive.
The purpose is to ensure no regressions will appear when some JavaScript dependencies
or our custom frontend code evolve.
A first batch of tests will check that almost all the programming languages supported by the
highlightjs library are correctly highlighted.
The other tests will check that some special contents (images, pdf files, ...) will be
correctly rendered.
In order to provide relevant input data to these new tests, some new endpoints are added
to swh-web for that purpose (only available when running the end to end tests).
This is still a work in progress: a lot of supported programming languages and other special
contents to test are currently missing.
Related T1845