diff -r 000000000000 -r 6474c204b198 browser/components/downloads/test/unit/test_DownloadsCommon.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/downloads/test/unit/test_DownloadsCommon.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,37 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests for the functions located directly in the "DownloadsCommon" object.
+ */
+
+function testFormatTimeLeft(aSeconds, aExpectedValue, aExpectedUnitString)
+{
+  let expected = "";
+  if (aExpectedValue) {
+    // Format the expected result based on the current language.
+    expected = DownloadsCommon.strings[aExpectedUnitString](aExpectedValue);
+  }
+  do_check_eq(DownloadsCommon.formatTimeLeft(aSeconds), expected);
+}
+
+function run_test()
+{
+  testFormatTimeLeft(      0,   "", "");
+  testFormatTimeLeft(      1,  "1", "shortTimeLeftSeconds");
+  testFormatTimeLeft(     29, "29", "shortTimeLeftSeconds");
+  testFormatTimeLeft(     30, "30", "shortTimeLeftSeconds");
+  testFormatTimeLeft(     31,  "1", "shortTimeLeftMinutes");
+  testFormatTimeLeft(     60,  "1", "shortTimeLeftMinutes");
+  testFormatTimeLeft(     89,  "1", "shortTimeLeftMinutes");
+  testFormatTimeLeft(     90,  "2", "shortTimeLeftMinutes");
+  testFormatTimeLeft(     91,  "2", "shortTimeLeftMinutes");
+  testFormatTimeLeft(   3600,  "1", "shortTimeLeftHours");
+  testFormatTimeLeft(  86400, "24", "shortTimeLeftHours");
+  testFormatTimeLeft( 169200, "47", "shortTimeLeftHours");
+  testFormatTimeLeft( 172800,  "2", "shortTimeLeftDays");
+  testFormatTimeLeft(8553600, "99", "shortTimeLeftDays");
+  testFormatTimeLeft(8640000, "99", "shortTimeLeftDays");
+}