Add test for @at-root feature

[lunelson]

A tentative test suite for @at-root, covering the cases I can think of

sass/libsass#353

[KittyGiraudel]

For sass-compatibility, we are running some tests from sass-spec, including this one. Unfortunately, Sass 3.3 chokes on this test because of the keyframe directive, which is completely unrelated to @at-root whatsoever.

Consider this test:

.baz {
  color: red;

  @keyframes kf2 {
    from: 0;
    to: 100;
  }
}

Sass 3.3:

.baz {
  color: red;
}
@keyframes kf2 {
  .baz {
    from: 0;
    to: 100;
  }
}

Sass 3.4:

.baz {
  color: red;
}
@keyframes kf2 {
  from: 0;
  to: 100;
}

Sass 3.3 does not output a nested @keyframes block at root level. It has nothing to do with the @at-root directive, which is perfectly supported by Sass 3.3.

Could we, by any chance, remove this nested @keyframes block from this test so Sass 3.3 can report positive, as it should do?

[xzyfer]

I agree for a couple different reasons.

@at-root is a large feature much like maps or @extends. With that in mind I say we create a spec/libsass/at-root folder with a series of granular cases. This will help greatly with debugging and implementing the feature.

I also think @hugogiraudel's sass-compatibility project (or something like it) is important for the community. As I've discussed on the sass-compatibility project feature support is not boolean. It's certainly worth while to know the aspects of a feature and be able to at a glance determine partial implementations.

Did you want to tackle this @hugogiraudel putting together a good series of specs for spec/libsass/at-root?

[KittyGiraudel]

I also think @hugogiraudel's sass-compatibility project (or something like it) is important for the community. As I've discussed on the sass-compatibility project feature support is not boolean. It's certainly worth while to know the aspects of a feature and be able to at a glance determine partial implementations.

@valeriangalliat has done one hell of a job to make it possible for me to pull tests from sass-spec, while still being able to have my own tests when necessary. Along the same lines, sass-compatibility will soon provide a "mixed state", where it's neither fully supported nor completely absent. With this will come a way to know what tests passed and what tests failed.

Did you want to tackle this @hugogiraudel putting together a good series of specs for spec/libsass/at-root?

Count me in.