Bug 1724319 - fix accessibility test relying on the download modal opening to work with download improvements pref flipped, r=Jamie

Differential Revision: https://phabricator.services.mozilla.com/D127487

accessible/tests/mochitest/states/test_doc_busy.html

@@ -20,6 +20,8 @@
   <script type="application/javascript">
     const { BrowserTestUtils } = ChromeUtils.import(
       "resource://testing-common/BrowserTestUtils.jsm");
+    const { Downloads } = ChromeUtils.import(
+      "resource://gre/modules/Downloads.jsm");
 
     function matchDocBusyChange(isBusy) {
       return function(event) {
@@ -32,6 +34,33 @@
       };
     }
 
+    function getDownloadStartedPromise() {
+      if (Services.prefs.getBoolPref("browser.download.improvements_to_download_panel", false)) {
+        return Downloads.getList(Downloads.PUBLIC).then(list => {
+          return new Promise(resolve => {
+            list.addView({
+              onDownloadAdded(download) {
+                resolve(download);
+              }
+            })
+          });
+        });
+      }
+      return BrowserTestUtils.domWindowOpenedAndLoaded(
+        null,
+        win => win.location?.href == "chrome://mozapps/content/downloads/unknownContentType.xhtml"
+      );
+    }
+
+    async function downloadHandled(downloadResult) {
+      if (Window.isInstance(downloadResult)) {
+        return BrowserTestUtils.closeWindow(downloadResult);
+      }
+      // downloadResult is a download object.
+      await downloadResult.finalize(true);
+      return Downloads.getList(Downloads.PUBLIC).then(list => list.remove(downloadResult));
+    }
+
     async function doTest() {
       // Because of variable timing, there are two acceptable possibilities:
       // 1. We get an event for busy and an event for not busy.
@@ -40,10 +69,6 @@
       // second.
       let gotBusy = false;
       let gotNotBusy = false;
-      // We never actually wait on this; we just check the booleans it sets.
-      // We still need to hold a reference so it doesn't get garbage collected
-      // before it does anything.
-      // eslint-disable-next-line no-unused-vars
       const busyEvents = async function() {
         await waitForEvent(EVENT_STATE_CHANGE, matchDocBusyChange(true));
         info("Got busy event");
@@ -53,20 +78,18 @@
         gotNotBusy = true;
       }();
 
-      const downloadPromptOpened = BrowserTestUtils.domWindowOpened(null,
-        async win => {
-          info("Window opened, waiting for load event");
-          await BrowserTestUtils.waitForEvent(win, "load");
-          info("Window loaded, checking if download prompt");
-          return win.location &&
-            win.location.href == "chrome://mozapps/content/downloads/unknownContentType.xhtml";
-        }
-      );
+      const downloadStarted = getDownloadStartedPromise();
 
       info("Clicking link to trigger download");
       synthesizeMouse(getNode("link"), 1, 1, {});
       info("Waiting for download prompt to open");
-      const downloadWin = await downloadPromptOpened;
+      const downloadResult = await downloadStarted;
+
+      // Once we no longer show a dialog for downloads, the not busy event
+      // might show up a bit later.
+      if (gotBusy && !gotNotBusy) {
+        await busyEvents;
+      }
 
       // Any busy events should have been fired by the time the download
       // prompt has opened.
@@ -81,7 +104,7 @@
 
       // Clean up.
       info("Closing download prompt");
-      downloadWin.close();
+      await downloadHandled(downloadResult);
       // We might still be waiting on busy events. Remove any pending observers.
       for (let observer of Services.obs.enumerateObservers(
         "accessible-event")