diff -r 000000000000 -r 6474c204b198 toolkit/components/thumbnails/test/browser_thumbnails_storage_migrate3.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/components/thumbnails/test/browser_thumbnails_storage_migrate3.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,106 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const URL = "http://mochi.test:8888/migration3";
+const URL2 = URL + "#2";
+const URL3 = URL + "#3";
+const THUMBNAIL_DIRECTORY = "thumbnails";
+const PREF_STORAGE_VERSION = "browser.pagethumbnails.storage_version";
+
+let tmp = {};
+Cc["@mozilla.org/moz/jssubscript-loader;1"]
+  .getService(Ci.mozIJSSubScriptLoader)
+  .loadSubScript("resource://gre/modules/PageThumbs.jsm", tmp);
+let {PageThumbsStorageMigrator} = tmp;
+
+XPCOMUtils.defineLazyServiceGetter(this, "gDirSvc",
+  "@mozilla.org/file/directory_service;1", "nsIProperties");
+
+/**
+ * This test makes sure we correctly migrate to thumbnail storage version 3.
+ * This means copying existing thumbnails from the roaming to the local profile
+ * directory and should just apply to Linux.
+ */
+function runTests() {
+  let dirSvc = Cc["@mozilla.org/file/directory_service;1"]
+                 .getService(Ci.nsIProperties);
+
+  // Prepare a local profile directory.
+  let localProfile = FileUtils.getDir("ProfD", ["local-test"], true);
+  changeLocation("ProfLD", localProfile);
+
+  let local = FileUtils.getDir("ProfLD", [THUMBNAIL_DIRECTORY], true);
+  let roaming = FileUtils.getDir("ProfD", [THUMBNAIL_DIRECTORY], true);
+
+  // Set up some data in the roaming profile.
+  let name = PageThumbsStorage.getLeafNameForURL(URL);
+  let file = FileUtils.getFile("ProfD", [THUMBNAIL_DIRECTORY, name]);
+  writeDummyFile(file);
+
+  name = PageThumbsStorage.getLeafNameForURL(URL2);
+  file = FileUtils.getFile("ProfD", [THUMBNAIL_DIRECTORY, name]);
+  writeDummyFile(file);
+
+  name = PageThumbsStorage.getLeafNameForURL(URL3);
+  file = FileUtils.getFile("ProfD", [THUMBNAIL_DIRECTORY, name]);
+  writeDummyFile(file);
+
+  // Pretend to have one of the thumbnails
+  // already in place at the new storage site.
+  name = PageThumbsStorage.getLeafNameForURL(URL3);
+  file = FileUtils.getFile("ProfLD", [THUMBNAIL_DIRECTORY, name]);
+  writeDummyFile(file, "no-overwrite-plz");
+
+  // Kick off thumbnail storage migration.
+  PageThumbsStorageMigrator.migrateToVersion3(localProfile.path);
+  ok(true, "migration finished");
+
+  // Wait until the first thumbnail was moved to its new location.
+  yield whenFileExists(URL);
+  ok(true, "first thumbnail moved");
+
+  // Wait for the second thumbnail to be moved as well.
+  yield whenFileExists(URL2);
+  ok(true, "second thumbnail moved");
+
+  yield whenFileRemoved(roaming);
+  ok(true, "roaming thumbnail directory removed");
+
+  // Check that our existing thumbnail wasn't overwritten.
+  is(getFileContents(file), "no-overwrite-plz",
+    "existing thumbnail was not overwritten");
+
+  // Sanity check: ensure that, until it is removed, deprecated
+  // function |getFileForURL| points to the same path as
+  // |getFilePathForURL|.
+  if ("getFileForURL" in PageThumbsStorage) {
+    let file = PageThumbsStorage.getFileForURL(URL);
+    is(file.path, PageThumbsStorage.getFilePathForURL(URL),
+       "Deprecated getFileForURL and getFilePathForURL return the same path");
+  }
+}
+
+function changeLocation(aLocation, aNewDir) {
+  let oldDir = gDirSvc.get(aLocation, Ci.nsILocalFile);
+  gDirSvc.undefine(aLocation);
+  gDirSvc.set(aLocation, aNewDir);
+
+  registerCleanupFunction(function () {
+    gDirSvc.undefine(aLocation);
+    gDirSvc.set(aLocation, oldDir);
+  });
+}
+
+function writeDummyFile(aFile, aContents) {
+  let fos = FileUtils.openSafeFileOutputStream(aFile);
+  let data = aContents || "dummy";
+  fos.write(data, data.length);
+  FileUtils.closeSafeFileOutputStream(fos);
+}
+
+function getFileContents(aFile) {
+  let istream = Cc["@mozilla.org/network/file-input-stream;1"]
+                  .createInstance(Ci.nsIFileInputStream);
+  istream.init(aFile, FileUtils.MODE_RDONLY, FileUtils.PERMS_FILE, 0);
+  return NetUtil.readInputStreamToString(istream, istream.available());
+}