1 files changed, 45 insertions, 0 deletions
diff --git a/browser/components/newtab/test/browser/abouthomecache/browser_shutdown_timeout.js b/browser/components/newtab/test/browser/abouthomecache/browser_shutdown_timeout.js
new file mode 100644
index 0000000000..52be79338e
--- /dev/null
+++ b/browser/components/newtab/test/browser/abouthomecache/browser_shutdown_timeout.js
@@ -0,0 +1,45 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Tests that if there's a substantial delay in getting the cache
+ * streams from the privileged about content process for any reason
+ * during shutdown, that we timeout and let the AsyncShutdown proceed,
+ * rather than letting it block until AsyncShutdown causes a shutdown
+ * hang crash.
+ */
+add_task(async function test_shutdown_timeout() {
+  await withFullyLoadedAboutHome(async browser => {
+    // First, make sure the cache is populated so that later on, after
+    // the timeout, simulateRestart doesn't complain about not finding
+    // a pre-existing cache. This complaining only happens if this test
+    // is run in isolation.
+    await clearCache();
+    await simulateRestart(browser);
+
+    // Next, manually shutdown the AboutHomeStartupCacheChild so that
+    // it doesn't respond to requests to the cache streams.
+    await SpecialPowers.spawn(browser, [], async () => {
+      let { AboutHomeStartupCacheChild } = ChromeUtils.import(
+        "resource:///modules/AboutNewTabService.jsm"
+      );
+      AboutHomeStartupCacheChild.uninit();
+    });
+
+    // Then, manually dirty the cache state so that we attempt to write
+    // on shutdown.
+    AboutHomeStartupCache.onPreloadedNewTabMessage();
+
+    await simulateRestart(browser, { expectTimeout: true });
+
+    Assert.ok(
+      true,
+      "We reached here, which means shutdown didn't block forever."
+    );
+
+    // Clear the cache so that we're not in a half-persisted state.
+    await clearCache();
+  });
+});