CSSOM: add CSSStyleDeclaration cssText setter tests

css/cssom/cssstyledeclaration-csstext-setter.window.js

@@ -0,0 +1,64 @@
+// https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-csstext
+
+[
+  document.body,
+  document.createElement("cool-beans")
+].forEach(element => {
+  test(t => {
+    t.add_cleanup(() => element.removeAttribute("style"));
+
+    element.style.background = "red";
+    assert_equals(element.getAttribute("style"), "background: red;");
+
+    element.style.cssText = "background:red";
+    assert_equals(element.getAttribute("style"), "background: red;");
+  }, `cssText setter should set style attribute even when there are no style changes (${element.localName})`);
+
+  test(t => {
+    t.add_cleanup(() => element.removeAttribute("style"));
+
+    element.setAttribute("style", "background:   red");
+    assert_equals(element.getAttribute("style"), "background:   red");
+
+    element.style.cssText = "background:red";
+    assert_equals(element.getAttribute("style"), "background: red;");
+  }, `cssText setter should set style attribute even when there are no style changes, part 2 (${element.localName})`);
+
+  test(t => {
+    t.add_cleanup(() => element.removeAttribute("style"));
+
+    element.setAttribute("style", "background:   red");
+    assert_equals(element.getAttribute("style"), "background:   red");
+
+    element.style.cssText = "background:red "; // trailing space
+    assert_equals(element.getAttribute("style"), "background: red;");
+  }, `cssText setter should set style attribute even when there are no style changes, part 3 (${element.localName})`);
+
+  test(t => {
+    t.add_cleanup(() => element.removeAttribute("style"));
+
+    element.setAttribute("style", "background:   red");
+    assert_equals(element.getAttribute("style"), "background:   red");
+
+    element.style.cssText = "background:red;";
+    assert_equals(element.getAttribute("style"), "background: red;");
+  }, `cssText setter should set style attribute even when there are no style changes, part 4 (${element.localName})`);
+});
+
+test(t => {
+  const style = document.createElement("style");
+  t.add_cleanup(() => {
+    document.body.removeAttribute("style");
+    style.remove();
+  });
+  style.textContent = `[style="background: red;"] { background:white !important; }`;
+  document.body.appendChild(style);
+
+  document.body.setAttribute("style", "background:red");
+  assert_true(document.body.matches("[style=\"background:red\"]"));
+  assert_equals(getComputedStyle(document.body).backgroundColor, "rgb(255, 0, 0)");
+
+  document.body.style.cssText = "background:red";
+  assert_equals(getComputedStyle(document.body).backgroundColor, "rgb(255, 255, 255)");
+  assert_true(document.body.matches("[style=\"background: red;\"]"));
+}, `cssText setter and selector invalidation`);

lint.ignore

@@ -580,6 +580,7 @@ MISSING-LINK: css/cssom-view/scrollTop-display-change.html
 # TODO https://github.com/web-platform-tests/wpt/issues/5770
 MISSING-LINK: css/css-highlight-api/idlharness.window.js
 MISSING-LINK: css/css-highlight-api/historical.window.js
+MISSING-LINK: css/cssom/cssstyledeclaration-csstext-setter.window.js
 MISSING-LINK: css/geometry/*.worker.js
 MISSING-LINK: css/geometry/*.any.js
 MISSING-LINK: css/filter-effects/*.any.js