diff -r 000000000000 -r 6474c204b198 toolkit/mozapps/update/tests/unit_base_updater/marFileInUseSuccessComplete_win.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/mozapps/update/tests/unit_base_updater/marFileInUseSuccessComplete_win.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,38 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+/* File in use complete MAR file patch apply success test */
+
+function run_test() {
+  setupTestCommon();
+  gTestFiles = gTestFilesCompleteSuccess;
+  gTestDirs = gTestDirsCompleteSuccess;
+  setupUpdaterTest(FILE_COMPLETE_MAR, false, true);
+
+  // Launch an existing file so it is in use during the update.
+  let fileInUseBin = getApplyDirFile(gTestFiles[13].relPathDir +
+                                     gTestFiles[13].fileName);
+  let args = [getApplyDirPath() + "a/b/", "input", "output", "-s",
+              HELPER_SLEEP_TIMEOUT];
+  let fileInUseProcess = AUS_Cc["@mozilla.org/process/util;1"].
+                         createInstance(AUS_Ci.nsIProcess);
+  fileInUseProcess.init(fileInUseBin);
+  fileInUseProcess.run(false, args, args.length);
+
+  do_timeout(TEST_HELPER_TIMEOUT, waitForHelperSleep);
+}
+
+function doUpdate() {
+  runUpdate(0, STATE_SUCCEEDED);
+}
+
+function checkUpdateApplied() {
+  setupHelperFinish();
+}
+
+function checkUpdate() {
+  checkFilesAfterUpdateSuccess();
+  checkUpdateLogContains(ERR_BACKUP_DISCARD);
+  checkCallbackAppLog();
+}