1 files changed, 34 insertions, 9 deletions

diff --git a/browser/base/content/test/general/browser_minimize.js b/browser/base/content/test/general/browser_minimize.js
index a57fea079c..3919cd7d77 100644
--- a/browser/base/content/test/general/browser_minimize.js
+++ b/browser/base/content/test/general/browser_minimize.js
@@ -12,26 +12,57 @@ add_task(async function () {
   ok(isActive(), "Docshell should be active when starting the test");
   ok(!document.hidden, "Top level window should be visible");
 
+  // When we show or hide the window (including by minimization),
+  // there are 2 signifiers that the process is complete: the
+  // sizemodechange event, and the browsing context becoming active
+  // or inactive. There is another signifier, the
+  // occlusionstatechange event, but whether or not that event
+  // is sent is platform-dependent, so it's not very useful. The
+  // safest way to check for stable state is to build promises
+  // around sizemodechange and browsing context active and then
+  // wait for them all to complete, and that's what we do here.
   info("Calling window.minimize");
   let promiseSizeModeChange = BrowserTestUtils.waitForEvent(
     window,
     "sizemodechange"
+  ).then(
+    () => ok(true, "Got sizemodechange."),
+    () => ok(false, "Rejected sizemodechange.")
+  );
+  let promiseBrowserInactive = BrowserTestUtils.waitForCondition(
+    () => !isActive(),
+    "Docshell should be inactive."
+  ).then(
+    () => ok(true, "Got inactive."),
+    () => ok(false, "Rejected inactive.")
   );
   window.minimize();
-  await promiseSizeModeChange;
-  ok(!isActive(), "Docshell should be Inactive");
+  await Promise.all([promiseSizeModeChange, promiseBrowserInactive]);
   ok(document.hidden, "Top level window should be hidden");
 
+  // When we restore the window from minimization, we have the
+  // same concerns as above, so prepare our promises.
   info("Calling window.restore");
   promiseSizeModeChange = BrowserTestUtils.waitForEvent(
     window,
     "sizemodechange"
+  ).then(
+    () => ok(true, "Got sizemodechange."),
+    () => ok(false, "Rejected sizemodechange.")
+  );
+  let promiseBrowserActive = BrowserTestUtils.waitForCondition(
+    () => isActive(),
+    "Docshell should be active."
+  ).then(
+    () => ok(true, "Got active."),
+    () => ok(false, "Rejected active.")
   );
   window.restore();
+
   // On Ubuntu `window.restore` doesn't seem to work, use a timer to make the
   // test fail faster and more cleanly than with a test timeout.
   await Promise.race([
-    promiseSizeModeChange,
+    Promise.all([promiseSizeModeChange, promiseBrowserActive]),
     new Promise((resolve, reject) =>
       // eslint-disable-next-line mozilla/no-arbitrary-setTimeout
       setTimeout(() => {
@@ -39,11 +70,5 @@ add_task(async function () {
       }, 5000)
     ),
   ]);
-  // The sizemodechange event can sometimes be fired before the
-  // occlusionstatechange event, especially in chaos mode.
-  if (window.isFullyOccluded) {
-    await BrowserTestUtils.waitForEvent(window, "occlusionstatechange");
-  }
-  ok(isActive(), "Docshell should be active again");
   ok(!document.hidden, "Top level window should be visible");
 });