1 files changed, 37 insertions, 0 deletions
diff --git a/browser/components/newtab/test/browser/abouthomecache/browser_no_cache_on_SessionStartup_restore.js b/browser/components/newtab/test/browser/abouthomecache/browser_no_cache_on_SessionStartup_restore.js
new file mode 100644
index 0000000000..a312b2b44f
--- /dev/null
+++ b/browser/components/newtab/test/browser/abouthomecache/browser_no_cache_on_SessionStartup_restore.js
@@ -0,0 +1,37 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Tests that if somehow about:newtab loads before about:home does, that we
+ * don't use the cache. This is because about:newtab doesn't use the cache,
+ * and so it'll inevitably be newer than what's in the about:home cache,
+ * which will put the about:home cache out of date the next time about:home
+ * eventually loads.
+ */
+add_task(async function test_no_cache_on_SessionStartup_restore() {
+  await withFullyLoadedAboutHome(async browser => {
+    await simulateRestart(browser, { skipAboutHomeLoad: true });
+
+    // We remove the preloaded browser to ensure that loading the next
+    // about:newtab occurs now, and not at preloading time.
+    NewTabPagePreloading.removePreloadedBrowser(window);
+    let tab = await BrowserTestUtils.openNewForegroundTab(
+      gBrowser,
+      "about:newtab"
+    );
+
+    let newWin = await BrowserTestUtils.openNewBrowserWindow();
+
+    // The cache is disqualified because about:newtab was loaded first.
+    // So now it's too late to use the cache.
+    await ensureDynamicAboutHome(
+      newWin.gBrowser.selectedBrowser,
+      AboutHomeStartupCache.CACHE_RESULT_SCALARS.LATE
+    );
+
+    await BrowserTestUtils.closeWindow(newWin);
+    await BrowserTestUtils.removeTab(tab);
+  });
+});