diff -r 000000000000 -r 6474c204b198 toolkit/components/search/tests/xpcshell/test_nocache.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/components/search/tests/xpcshell/test_nocache.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,101 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+let Cu = Components.utils;
+let Ci = Components.interfaces;
+
+Cu.import("resource://gre/modules/osfile.jsm");
+Cu.import("resource://gre/modules/Task.jsm");
+Cu.import("resource://testing-common/httpd.js");
+
+/*
+ * test_nocache: Start search engine
+ * - without search.json
+ *
+ * Ensure that :
+ * - nothing explodes;
+ * - search.json is created.
+ */
+
+
+function run_test()
+{
+  removeCache();
+  updateAppInfo();
+  do_load_manifest("data/chrome.manifest");
+
+  let httpServer = new HttpServer();
+  httpServer.start(-1);
+  httpServer.registerDirectory("/", do_get_cwd());
+
+  let search = Services.search;
+
+  do_test_pending();
+
+  // Check that cache is created at startup
+  afterCache(function cacheCreated() {
+    // Check that search.json has been created.
+    let cache = gProfD.clone();
+    cache.append("search.json");
+    do_check_true(cache.exists());
+  });
+
+  // Perform initialization
+  search.init(function ss_initialized(rv) {
+    do_check_true(Components.isSuccessCode(rv));
+
+    do_print("Setting up observer");
+    function observer(aSubject, aTopic, aData) {
+      do_print("Observing topic " + aTopic);
+      if ("engine-added" == aData) {
+        let engine = search.getEngineByName("Test search engine");
+        if (!engine) {
+          return;
+        }
+        Services.obs.removeObserver(observer, "browser-search-engine-modified");
+        do_print("Engine has been added, let's wait for the cache to be built");
+        afterCache(function() {
+          do_print("Success");
+
+          Task.spawn(function task() {
+            do_print("Searching test engine in cache");
+            try {
+              let path = OS.Path.join(OS.Constants.Path.profileDir, "search.json");
+              let data = yield OS.File.read(path);
+              let text = new TextDecoder().decode(data);
+              let cache = JSON.parse(text);
+              let found = false;
+              for (let dirName in cache.directories) {
+                for (let engine of cache.directories[dirName].engines) {
+                  if (engine._id == "[app]/test-search-engine.xml") {
+                    found = true;
+                    break;
+                  }
+                }
+                if (found) {
+                  break;
+                }
+              }
+              do_check_true(found);
+            } catch (ex) {
+              do_throw(ex);
+            } finally {
+              removeCache();
+              httpServer.stop(function() {
+                // httpServer doesn't seem to stop cleanly if there is no callback
+              });
+              do_test_finished();
+            }
+          });
+        });
+      }
+    };
+    Services.obs.addObserver(observer, "browser-search-engine-modified", false);
+
+    // Add an engine, check if it appears in the cache
+    search.addEngine("http://localhost:" + httpServer.identity.primaryPort +
+                     "/data/engine.xml",
+                     Ci.nsISearchEngine.DATA_XML,
+                     null, false);
+  });
+}