[FEATURE] Parse container queries

[scq]

Adds support for CSS container queries.

https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Containment/Container_queries

@container (width > 700px) {
  .card h2 {
    font-size: 2em;
  }
}

[coveralls]

coverage: 59.658%. remained the same
when pulling 45830cd on totara:container-queries
into fe29992 on MyIntervals:main.

[JakeQZ]

Looks good.

Could you also add a test to confirm the feature - ideally introducing an AtRuleTest TestCase? And add an entry to CHANGELOG.md?

Thanks.

[scq]

Thanks! Added a test here, it's a little difficult to test being an interface so it just checks the value of the property, but open to any better ideas you have.

[JakeQZ]

Thanks again.

it's a little difficult to test being an interface so it just checks the value of the property

My apologies. When looking at the diffs without full context, I was thinking that AtRule was a class.

The test you have added I think a is good to check to have for the internal behaviour (and fulfills the criteria: fails without the change; passes with). Though it seems PHPStan does not like a @covers annotation for an interface.

but open to any better ideas you have.

I've now done a bit of digging around the code base and existing tests and found that we have tests/CSSList/AtRuleBlockListTest.php. This has a test method parsesSyntacticallyCorrectAtRuleInStrictMode which checks that the at-rule is not discarded.

So I think to test the external beviour, it would good to have the provideSyntacticallyCorrectAtRule() data provider also provide a valid @contianer rule, which I expect would fail without the change. I think that would be sufficient (it's all we have for the other at-rules).

@oliverklee, do you have any other comments?

[JakeQZ]

Good choice of assert method - it allows the components to be in any order.

[scq]

Aha! Thanks, good find -- I've added a @container entry to the provideSyntacticallyCorrectAtRule data provider.

[JakeQZ]

LGTM now. Thanks <3