initial at-root tests

tests/at-root.rs

@@ -0,0 +1,30 @@
+#![cfg(test)]
+
+#[macro_use]
+mod macros;
+
+test!(
+    simple_nested,
+    ".foo {\n  @at-root {\n    .bar {a: b}\n  }\n}\n"
+    ".bar {\n  a: b;\n}\n"
+);
+test!(
+    with_selector,
+    ".foo {\n  @at-root .bar {a: b}\n}\n"
+    ".bar {\n  a: b;\n}\n"
+);
+test!(
+    with_selector_in_mixin,
+    "@mixin bar {\n  @at-root .bar {a: b}\n}\n\n.foo {\n  @include bar;\n}\n"
+    ".bar {\n  a: b;\n}\n"
+);
+test!(
+    with_super_selector,
+    ".foo {\n  @at-root & {\n    a: b;\n  }\n}\n"
+    ".foo {\n  a: b;\n}\n"
+);
+test!(
+    nested_with_super_selector,
+    ".foo {\n  @at-root & {\n    .bar {\n      @at-root & {\n        a: b;\n      }\n    }\n  }\n}\n"
+    ".foo .bar {\n  a: b;\n}\n"
+);