Add "scroll-behavior: auto" CSS to Capybara::Server::AnimationDisabler

[ndbroadbent]

I have some test cases where I need to call page.execute_script('window.scrollTo(0, 0)') before taking a screenshot. I'm using Tabler, which sets scroll-behavior: smooth;, so any scroll actions are smoothly animated. This is nice in production, but annoying during tests.

This proposed change will cause the scroll to always complete instantly without any animations. (This will only work when using the default selector_for value of '*', so that the rule matches the html element.)

scroll-behavior: auto is the default value, so I don't think this change should cause any problems.

I've added some tests, including an "inverse" test for Capybara.disable_animation = false. I think this important to show that scroll-behavior: smooth; does affect the scrolling speed, so that the test will have no false negatives.

EDIT: I just remembered another change that I made in my own version:

caret-color: transparent;

This is also very helpful during some of my screenshot diff tests where I'm checking that form inputs are rendered and filled in correctly.

Would it be ok to add caret-color: transparent;? I would love to start using the built-in AnimationDisabler from Capybara, but I really need this caret-color: transparent; as well. Or would it be possible to add the option to inject my own custom CSS?

EDIT 2: What do you think about this disable_animation_extra_properties change, so that I can set Capybara.disable_animation_extra_properties = 'caret-color: transparent;'?

[ndbroadbent]

It looks like I'm seeing the same test failure as the master branch, but otherwise all the tests are passing.

• PR: https://travis-ci.org/github/teamcapybara/capybara/jobs/731188374
• master: https://travis-ci.org/github/teamcapybara/capybara/jobs/731115454

[twalpole]

Thanks for this - I've made one comment around the tests, and you also have rubocop style failures - https://travis-ci.org/github/teamcapybara/capybara/jobs/731188375. You can run `bundle exec rubocop' before committing

[ndbroadbent]

Thanks for the review @twalpole! I've updated the tests with your suggestions, and also fixed all the style failures (sorry about those!)

[twalpole]

Thanks! LGTM