1 files changed, 101 insertions, 0 deletions
diff --git a/devtools/client/inspector/markup/test/browser_markup_overflow_badge.js b/devtools/client/inspector/markup/test/browser_markup_overflow_badge.js
new file mode 100644
index 0000000000..6770929594
--- /dev/null
+++ b/devtools/client/inspector/markup/test/browser_markup_overflow_badge.js
@@ -0,0 +1,101 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+// Tests that the overflow badge is shown to overflow causing elements and is updated
+// dynamically.
+
+const TEST_URI = `
+  <style type="text/css">
+    .parent {
+        width: 200px;
+        height: 200px;
+        overflow: scroll;
+    }
+    .fixed {
+        width: 50px;
+        height: 50px;
+    }
+    .shift {
+        margin-left: 300px;
+    }
+  </style>
+  <div id="top" class="parent">
+    <div id="child1" class="fixed shift">
+        <div id="child2" class="fixed"></div>
+    </div>
+    <div id="child3" class="shift">
+        <div id="child4" class="fixed"></div>
+    </div>
+  </div>
+`;
+
+add_task(async function () {
+  const { inspector } = await openInspectorForURL(
+    "data:text/html;charset=utf-8," + encodeURIComponent(TEST_URI)
+  );
+
+  await expandChildContainers(inspector);
+
+  const child1 = await getContainerForSelector("#child1", inspector);
+  const child2 = await getContainerForSelector("#child2", inspector);
+  const child3 = await getContainerForSelector("#child3", inspector);
+  const child4 = await getContainerForSelector("#child4", inspector);
+
+  info(
+    "Checking if overflow badges appear correctly right after the markup-view is loaded"
+  );
+
+  checkBadges([child1, child4], [child2, child3]);
+
+  info("Changing the elements to check whether the badge updates correctly");
+
+  await toggleClass(inspector);
+
+  checkBadges([child2, child3], [child1, child4]);
+
+  info(
+    "Once again, changing the elements to check whether the badge updates correctly"
+  );
+
+  await toggleClass(inspector);
+
+  checkBadges([child1, child4], [child2, child3]);
+});
+
+async function expandChildContainers(inspector) {
+  const container = await getContainerForSelector("#top", inspector);
+
+  await expandContainer(inspector, container);
+  for (const child of container.getChildContainers()) {
+    await expandContainer(inspector, child);
+  }
+}
+
+async function toggleClass(inspector) {
+  const onStateChanged = inspector.walker.once("overflow-change");
+
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], async function () {
+    content.document.querySelector("#child1").classList.toggle("fixed");
+    content.document.querySelector("#child3").classList.toggle("fixed");
+  });
+
+  await onStateChanged;
+}
+
+function checkBadges(elemsWithBadges, elemsWithNoBadges) {
+  const hasBadge = elem =>
+    elem.elt.querySelector(
+      `#${elem.elt.children[0].id} > span.editor > .inspector-badge.overflow-badge`
+    );
+
+  for (const elem of elemsWithBadges) {
+    ok(hasBadge(elem), `Overflow badge exists in ${elem.node.id}`);
+  }
+
+  for (const elem of elemsWithNoBadges) {
+    ok(!hasBadge(elem), `Overflow badge does not exist in ${elem.node.id}`);
+  }
+}