Add a test:coverage script and better reports

[diegonvs]

Issue type (mark with x)

• 🤔 Question
• 🐛 Bug report
• 🎁 Feature request
• 🤷‍♀️ Other

Description

Currently, we have some modules implementing their own coverage scripts, but they don't have a standardized way to do it, like an HTML report. The idea of this issue is to discuss if we should add a coverage script for testing or not.

Desired behavior:

Better reports and a standardized way to run JS unit tests' coverage

Current behavior:

We have terminal reports like this one:

but when opening the detailed view using the generated HTML page, this content is shown:

... and we can't click inside these links to get better reports about branches/lines covered