Bug 1534674: Add a test for pseudo element which defines CSS variable. r=gl

Differential Revision: https://phabricator.services.mozilla.com/D38303

--HG--
extra : moz-landing-system : lando

devtools/client/inspector/rules/test/browser.ini

@@ -106,6 +106,8 @@ skip-if = (verify && !debug && os == 'win')
 [browser_rules_completion-popup-hidden-after-navigation.js]
 [browser_rules_content_01.js]
 [browser_rules_content_02.js]
+[browser_rules_variables-in-pseudo-element_01.js]
+[browser_rules_variables-in-pseudo-element_02.js]
 [browser_rules_variables_01.js]
 [browser_rules_variables_02.js]
 skip-if = e10s && debug # Bug 1250058 - Docshell leak on debug e10s

devtools/client/inspector/rules/test/browser_rules_variables-in-pseudo-element_01.js

@@ -0,0 +1,46 @@
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test for pseudo element which defines CSS variable.
+
+const TEST_URI = `
+  <style type='text/css'>
+    div::before {
+      color: var(--color);
+      --color: orange;
+    }
+
+    div {
+      color: var(--color);
+      --color: lime;
+    }
+  </style>
+  <div></div>
+`;
+
+add_task(async function() {
+  await addTab("data:text/html;charset=utf-8," + encodeURIComponent(TEST_URI));
+  const { inspector, view } = await openRuleView();
+  await selectNode("div", inspector);
+
+  info("Test the CSS variable which normal element is referring to");
+  checkCSSVariableOutput(
+    view,
+    "div",
+    "color",
+    "ruleview-variable",
+    "--color = lime"
+  );
+
+  info("Test the CSS variable which pseudo element is referring to");
+  checkCSSVariableOutput(
+    view,
+    "div::before",
+    "color",
+    "ruleview-variable",
+    "--color = orange"
+  );
+});

devtools/client/inspector/rules/test/browser_rules_variables-in-pseudo-element_02.js

@@ -0,0 +1,45 @@
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test for pseudo element which inherits CSS variable.
+
+const TEST_URI = `
+  <style type='text/css'>
+    div::before {
+      color: var(--color);
+    }
+
+    div {
+      color: var(--color);
+      --color: lime;
+    }
+  </style>
+  <div></div>
+`;
+
+add_task(async function() {
+  await addTab("data:text/html;charset=utf-8," + encodeURIComponent(TEST_URI));
+  const { inspector, view } = await openRuleView();
+  await selectNode("div", inspector);
+
+  info("Test the CSS variable which normal element is referring to");
+  checkCSSVariableOutput(
+    view,
+    "div",
+    "color",
+    "ruleview-variable",
+    "--color = lime"
+  );
+
+  info("Test the CSS variable which pseudo element is referring to");
+  checkCSSVariableOutput(
+    view,
+    "div::before",
+    "color",
+    "ruleview-variable",
+    "--color = lime"
+  );
+});