test_collapsibities_fix.diff

diff --git a/devtools/client/aboutdebugging-new/test/browser/browser_aboutdebugging_debug-target-pane_collapsibilities_interaction.js b/devtools/client/aboutdebugging-new/test/browser/browser_aboutdebugging_debug-target-pane_collapsibilities_interaction.js
--- a/devtools/client/aboutdebugging-new/test/browser/browser_aboutdebugging_debug-target-pane_collapsibilities_interaction.js
+++ b/devtools/client/aboutdebugging-new/test/browser/browser_aboutdebugging_debug-target-pane_collapsibilities_interaction.js
@@ -8,24 +8,27 @@
  */
 
 add_task(async function() {
   prepareCollapsibilitiesTest();
 
   const { document, tab } = await openAboutDebugging();
 
   for (const { title } of TARGET_PANES) {
-    const debugTargetPaneEl = getDebugTargetPane(title, document);
+    let debugTargetPaneEl = getDebugTargetPane(title, document);
 
     info("Check whether this pane is collapsed after clicking the title");
     await toggleCollapsibility(debugTargetPaneEl);
+    debugTargetPaneEl = getDebugTargetPane(title, document);
+
     assertCollapsibility(debugTargetPaneEl, title, true);
-
     info("Check whether this pane is expanded after clicking the title again");
     await toggleCollapsibility(debugTargetPaneEl);
+
+    debugTargetPaneEl = getDebugTargetPane(title, document);
     assertCollapsibility(debugTargetPaneEl, title, false);
   }
 
   await removeTab(tab);
 });
 
 function assertCollapsibility(debugTargetPaneEl, title, shouldCollapsed) {
   info("Check height of list");
diff --git a/devtools/client/aboutdebugging-new/test/browser/debug-target-pane_collapsibilities_head.js b/devtools/client/aboutdebugging-new/test/browser/debug-target-pane_collapsibilities_head.js
--- a/devtools/client/aboutdebugging-new/test/browser/debug-target-pane_collapsibilities_head.js
+++ b/devtools/client/aboutdebugging-new/test/browser/debug-target-pane_collapsibilities_head.js
@@ -29,17 +29,17 @@ const TARGET_PANES = [
     title: "Other Workers",
     pref: "devtools.aboutdebugging.collapsibilities.otherWorker",
   },
 ];
 
 // eslint-disable-next-line no-unused-vars
 function getDebugTargetPane(title, document) {
   for (const titleEl of document.querySelectorAll(".js-debug-target-pane-title")) {
-    if (titleEl.textContent !== title) {
+    if (!titleEl.textContent.startsWith(title)) {
       continue;
     }
 
     return titleEl.closest(".js-debug-target-pane");
   }
 
   return null;
 }
@@ -51,17 +51,16 @@ function prepareCollapsibilitiesTest() {
     Services.prefs.setBoolPref(pref, false);
   }
 }
 
 // eslint-disable-next-line no-unused-vars
 async function toggleCollapsibility(debugTargetPane) {
   debugTargetPane.querySelector(".js-debug-target-pane-title").click();
   // Wait for animation of collapse/expand.
-  const animations = debugTargetPane.ownerDocument.getAnimations();
-  await Promise.all(animations.map(animation => animation.finished));
+  await new Promise(r => setTimeout(r, 300));
 }
 
 registerCleanupFunction(() => {
   for (const { pref } of TARGET_PANES) {
     Services.prefs.clearUserPref(pref);
   }
 });