Add root specifiers test

Author: dqbd

test/fixtures/root-media-specifity-combined.css

@@ -0,0 +1,27 @@
+:root {
+	--size: 32px;
+}
+
+:root.dark {
+  --size: 64px;
+}
+
+
+@media (test) {
+  :root {
+    --size: 96px;
+  }
+
+  :root.dark {
+    --size: 128px;
+  }
+}
+
+:root {
+  --test-size: var(--size);
+}
+
+.hello.world {
+  background: red;
+	width: var(--test-size);
+}

test/fixtures/root-media-specifity-combined.expected.css

@@ -0,0 +1,21 @@
+.hello.world {
+	background: red;
+	width: 32px;
+}
+
+@media (test) {
+	.hello.world {
+		width: 96px;
+	}
+}
+
+@media (test) {
+	:root.dark .hello.world {
+		width: 128px;
+	}
+}
+
+
+:root.dark .hello.world {
+	width: 64px;
+}

test/fixtures/root-media-specifity.css

@@ -0,0 +1,23 @@
+:root {
+	--size: 32px;
+}
+
+:root.dark {
+  --size: 64px;
+}
+
+
+@media (test) {
+  :root.dark {
+    --size: 128px;
+  }
+}
+
+:root {
+  --test-size: var(--size);
+}
+
+.hello.world {
+  background: red;
+	width: var(--test-size);
+}

test/fixtures/root-media-specifity.expected.css

@@ -0,0 +1,14 @@
+.hello.world {
+	background: red;
+	width: 32px;
+}
+
+@media (test) {
+	:root.dark .hello.world {
+		width: 128px;
+	}
+}
+
+:root.dark .hello.world {
+	width: 64px;
+}

test/fixtures/root-specifity.css

@@ -0,0 +1,16 @@
+:root {
+	--size: 32px;
+}
+
+:root.dark {
+  --size: 64px;
+}
+
+:root {
+  --test-size: var(--size);
+}
+
+.hello.world {
+  background: red;
+	width: var(--test-size);
+}

test/fixtures/root-specifity.expected.css

@@ -0,0 +1,8 @@
+.hello.world {
+	background: red;
+	width: 32px;
+}
+
+:root.dark .hello.world {
+	width: 64px;
+}

test/test.js

@@ -129,7 +129,12 @@ describe('postcss-css-variables', function() {
 
 	test('should work with `!important` variable declarations', 'important-variable-declaration');
 
-
+	
+	describe(':root specifiers', () => {
+		test('specific :root classifiers', 'root-specifity');
+		test('specific :root classifiers in media queries', 'root-media-specifity');
+		test('specific :root classifiers in media queries + pure', 'root-media-specifity-combined', { preserveAtRulesOrder: true });
+	})
 
 	describe('with at-rules', function() {
 		test('should add rule declaration of property in @media', 'media-query');