1 files changed, 47 insertions, 0 deletions
diff --git a/devtools/client/inspector/rules/test/browser_rules_edit-variable.js b/devtools/client/inspector/rules/test/browser_rules_edit-variable.js
new file mode 100644
index 0000000000..0df57d9bf1
--- /dev/null
+++ b/devtools/client/inspector/rules/test/browser_rules_edit-variable.js
@@ -0,0 +1,47 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Test editing a CSS variable.
+
+const TEST_URI = `
+  <style type='text/css'>
+    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("Check the initial state of the --color variable");
+  checkCSSVariableOutput(
+    view,
+    "div",
+    "color",
+    "ruleview-variable",
+    "--color = lime"
+  );
+
+  info("Edit the CSS variable");
+  const prop = getTextProperty(view, 1, { "--color": "lime" });
+  const propEditor = prop.editor;
+  const editor = await focusEditableField(view, propEditor.valueSpan);
+  editor.input.value = "blue";
+  const onRuleViewChanged = view.once("ruleview-changed");
+  EventUtils.synthesizeKey("VK_RETURN", {}, view.styleWindow);
+  await onRuleViewChanged;
+  checkCSSVariableOutput(
+    view,
+    "div",
+    "color",
+    "ruleview-variable",
+    "--color = blue"
+  );
+});