1 files changed, 28 insertions, 0 deletions
diff --git a/toolkit/mozapps/downloads/tests/unit/test_syncedDownloadUtils.js b/toolkit/mozapps/downloads/tests/unit/test_syncedDownloadUtils.js
new file mode 100644
index 0000000000..d60baee447
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+++ b/toolkit/mozapps/downloads/tests/unit/test_syncedDownloadUtils.js
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test bug 420482 by making sure multiple consumers of DownloadUtils gets the
+ * same time remaining time if they provide the same time left but a different
+ * "last time".
+ */
+
+const { DownloadUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/DownloadUtils.sys.mjs"
+);
+
+function run_test() {
+  // Simulate having multiple downloads requesting time left
+  let downloadTimes = {};
+  for (let time of [1, 30, 60, 3456, 9999]) {
+    downloadTimes[time] = DownloadUtils.getTimeLeft(time)[0];
+  }
+
+  // Pretend we're a download status bar also asking for a time left, but we're
+  // using a different "last sec". We need to make sure we get the same time.
+  let lastSec = 314;
+  for (let [time, text] of Object.entries(downloadTimes)) {
+    Assert.equal(DownloadUtils.getTimeLeft(time, lastSec)[0], text);
+  }
+}