There are some BS artefacts that Behat doesn't like specially (it's unable to interact with them).

To workaround that... what we do is to "disable" the special artefact visualization and make it default to its standard representation (sliders are checkboxes...).

To do that we have been adding behat selectors to .scss files that, once complied end into the final theme .css files. All sites get those selectors.

This issue is about:

1) Move all the behat specific selectors to a particular file (say behat.scss for example.
2) Only consider that file when building the final .css if the site is a running behat site. Never if it's a normal site.

For the records, right now we have (38_STABLE) behat selectors in:

$ grep -lr behat

layout/columns2.php

scss/moodle/core.scss

scss/moodle/debug.scss

tests/behat/blacklist.json

style/moodle.css

We should be able to reduce that to just that proposed behat.scss file and ensure it's used when running behat site only.

Ciao