Adds style failing test case for Vue Testing Library

[joaopslins]

Test case reproducing issue #438.

From master, I ran yarn add @testing-library/vue --dev, and also had to bump @vue/test-utils to 1.3.0 otherwise it wouldn't work. I probably messed up something in the yarn.lock file so apologies for that.

I believe window.getComputedStyle API would work to assert this behavior based on it working here (https://codesandbox.io/s/vue-testing-sample-input-forked-drjsm?file=/src/components/Button.test.js). Let me know if there's a better way of testing that.

I'm not sure if this is the reproducible case you were looking for so if there's something else I can/should do please let me know so I can improve this PR. Thank you!

[lmiller1990]

Hi! Sorry for the slow reply. Can you try merging in master and pushing to see if CI passes?

[joaopslins]

@lmiller1990 Thanks for the reply. I've force-pushed pulling the changes from master. Looks like CI has some issue with setup maybe? Let me know how I can help.

[lmiller1990]

I enabled CI for this PR, let's see how it goes.

[joaopslins]

I think the test is still failing...

In any case, could you double check if my test is testing the right thing? As in, it should work that way?