Only apply extension throttling quota to sync, not local.

chrome/test/data/extensions/api_test/settings/simple_test/background.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 function test(stage0) {
   var apis = [
     chrome.storage.sync,
     chrome.storage.local
   ];
   apis.forEach(function(api) {
@@ skipping 316 matching lines @@
     function stage5(bytesInUse) {
       chrome.test.assertEq(6, bytesInUse);
       chrome.test.succeed();
     }
     area.clear(stage0);
   },
 
   // NOTE: throttling test must come last, since each test runs with a single
   // quota.
   function throttling() {
-    // We can only really test one of the namespaces since they will all get
-    // throttled together.
-    var api = chrome.storage.sync;
+    // Test script is as so:
+    //   1 - storage.local shouldn't be exceeded.
+    //   2 - storage.sync should be exceeded.
+    //   3 - storage.local still shouldn't be exceeded.
+    //   4 - storage.sync should still be exceeded.
+    //
+    // In general, things should get throttled after 1000 calls (though in
+    // reality will be fewer due to previous tests).
 
-    // Should get throttled after 1000 calls (though in reality will be fewer
-    // due to previous tests).
-    var maxRequests = 1001;
+    function clearNTimes(area, n, whenDone) {
+      if (n <= 0) {
+        whenDone();
+      } else {
+        area.clear(function() {
+          clearNTimes(area, n - 1, whenDone);
+        });
+      }
+    }
 
-    function next() {
-      api.clear((--maxRequests > 0) ? next : done);
-    }
-    function done() {
-      chrome.test.assertEq(
-          "This request exceeds available quota.",
-          chrome.extension.lastError.message);
-      chrome.test.succeed();
-    }
-    api.clear(next);
+    var local = chrome.storage.local;
+    var sync = chrome.storage.sync;
+    var test = chrome.test;
+    var quotaError = "This request exceeds available quota.";
+
+    clearNTimes(local, 1001, test.callbackPass(function() {
+      clearNTimes(sync, 1001, test.callbackFail(quotaError, function() {

[Matt Perry, 2012/04/27 18:48:03]

could you do sync and local in parallel?

[not at google - send to devlin, 2012/04/29 23:58:03]

hm, not sure, I definitely wanted to test those 4 conditions: that local doesn't
exceed, that sync does, that after quota is exceeded local still fails, and that
after local succeeds sync still fails.

After playing with doing it in parallel for a bit, it's a tiny bit messy to
express that "after 1000 writes, sync should have failed, and from then on
should always fail". I dunno, not that complicated, but more than this anyway.

+        clearNTimes(local, 1, test.callbackPass(function() {
+          clearNTimes(sync, 1, test.callbackFail(quotaError, test.succeed));
+        }));
+      }));
+    }));
   }
-
 ]);