Add regression test for getComputedStyle() liveness

asamuzaK · web-flow · commit d526a0743298 · 2026-03-20T18:43:33.000+09:00
See #3562.
diff --git a/test/web-platform-tests/to-upstream-expectations.yaml b/test/web-platform-tests/to-upstream-expectations.yaml
@@ -12,6 +12,7 @@ css/css-nesting/nested-media-in-layer.html: [fail, https://github.com/jsdom/jsdo
 css/css-values/calc-parentheses.html: [fail, calc() values not resolved to computed values; https://github.com/jsdom/jsdom/issues/3538]
 css/cssom/getComputedStyle-fontFamily.html:
   "Child element inherits the fontFamily value from its parent": [fail, https://github.com/jsdom/jsdom/issues/3614]
+css/cssom/getComputedStyle-live.html: [fail, https://github.com/jsdom/jsdom/issues/3562]
 css/cssom/getComputedStyle-opacity.html: [fail, https://github.com/jsdom/jsdom/issues/3339]
 css/cssom/getComputedStyle-root-variables.html: [fail, https://github.com/jsdom/jsdom/issues/3563]
 css/cssom/getComputedStyle-shadow-host.html: [fail, https://github.com/jsdom/jsdom/issues/3661]
diff --git a/test/web-platform-tests/to-upstream/css/cssom/getComputedStyle-live.html b/test/web-platform-tests/to-upstream/css/cssom/getComputedStyle-live.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>getComputedStyle() returns live values</title>
+<link rel="help" href="https://drafts.csswg.org/cssom/#dom-window-getcomputedstyle">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<!-- regression test for https://github.com/jsdom/jsdom/issues/3562 -->
+
+<div id="div"></div>
+
+<script>
+"use strict";
+
+test(() => {
+  const div = document.getElementById("div");
+  const computedStyles = window.getComputedStyle(div);
+  assert_equals(computedStyles.backgroundColor, "rgba(0, 0, 0, 0)", "before");
+
+  div.style.setProperty("background-color", "red");
+  assert_equals(computedStyles.backgroundColor, "rgb(255, 0, 0)", "after");
+});
+</script>
