Add assert.dom(...).hasStyle() assertion

[selvagsz]

Add assertions for styles like

assert.dom('.some-element').hasStyle({
  opacity: 1,
  width: '340px',
});

Fixes #90

supersedes #106

[selvagsz]

@Turbo87 this is how it renders on failure

[selvagsz]

Just saw there is yarn docs to generate the documentation. Will use it & update the pr

[selvagsz]

@Turbo87 fixed the docs & updated the tests. lmk if I'd missed anything else :)

[Turbo87]

what is this doing?

maybe something like this might be easier to read/understand:

let computedStyle = window.getComputedStyle(element);

let expectedProperties = Object.keys(expected);
let result = expectedProperties.every(property => computedStyle[property] === expected[property]);

let actual = {};
expectedProperties.forEach(property => actual[property] = computedStyle[property]);

[selvagsz]

refactored as suggested 👍

[jayjayjpg]

@Turbo87 @selvagsz Is it alright if I pick this one up? It would be sweet to see the work that has already been done land ✨

[gabrielcsapo]

@jessica-jordan please 🙏 this would be awesome to have!

[selvagsz]

Been working on product releases for a while. Sorry for the delay

[jayjayjpg]

✨

[Turbo87]

nice work, thanks @selvagsz!