diff -r 000000000000 -r 6474c204b198 dom/indexedDB/test/unit/test_traffic_jam.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/indexedDB/test/unit/test_traffic_jam.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,87 @@
+/**
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+var testGenerator = testSteps();
+
+function testSteps()
+{
+  const name = this.window ? window.location.pathname : "Splendid Test";
+
+  let requests = [];
+  function doOpen(version, errorCallback, upgradeNeededCallback, successCallback) {
+    let request = indexedDB.open(name, version);
+    request.onerror = errorCallback;
+    request.onupgradeneeded = upgradeNeededCallback;
+    request.onsuccess = successCallback;
+    requests.push(request);
+  }
+
+  doOpen(1, errorHandler, grabEventAndContinueHandler, grabEventAndContinueHandler);
+  doOpen(2, errorHandler, unexpectedSuccessHandler, unexpectedSuccessHandler);
+
+  let event = yield undefined;
+  is(event.type, "upgradeneeded", "expect an upgradeneeded event");
+  is(event.target, requests[0], "fired at the right request");
+
+  let db = event.target.result;
+  db.createObjectStore("foo");
+
+  doOpen(3, errorHandler, unexpectedSuccessHandler, unexpectedSuccessHandler);
+  doOpen(2, errorHandler, unexpectedSuccessHandler, unexpectedSuccessHandler);
+  doOpen(3, errorHandler, unexpectedSuccessHandler, unexpectedSuccessHandler);
+
+  event.target.transaction.oncomplete = grabEventAndContinueHandler;
+
+  event = yield undefined;
+  is(event.type, "complete", "expect a complete event");
+  is(event.target, requests[0].transaction, "expect it to be fired at the transaction");
+
+  event = yield undefined;
+  is(event.type, "success", "expect a success event");
+  is(event.target, requests[0], "fired at the right request");
+  event.target.result.close();
+
+  requests[1].onupgradeneeded = grabEventAndContinueHandler;
+
+  event = yield undefined;
+  is(event.type, "upgradeneeded", "expect an upgradeneeded event");
+  is(event.target, requests[1], "fired at the right request");
+
+  requests[1].onsuccess = grabEventAndContinueHandler;
+
+  event = yield undefined;
+  is(event.type, "success", "expect a success event");
+  is(event.target, requests[1], "fired at the right request");
+  event.target.result.close();
+
+  requests[2].onupgradeneeded = grabEventAndContinueHandler;
+
+  event = yield undefined;
+  is(event.type, "upgradeneeded", "expect an upgradeneeded event");
+  is(event.target, requests[2], "fired at the right request");
+
+  requests[2].onsuccess = grabEventAndContinueHandler;
+
+  event = yield undefined;
+  is(event.type, "success", "expect a success event");
+  is(event.target, requests[2], "fired at the right request");
+  event.target.result.close();
+
+  requests[3].onerror = null;
+  requests[3].addEventListener("error", new ExpectError("VersionError", true));
+
+  event = yield undefined;
+
+  requests[4].onsuccess = grabEventAndContinueHandler;
+
+  event = yield undefined;
+  is(event.type, "success", "expect a success event");
+  is(event.target, requests[4], "fired at the right request");
+  event.target.result.close();
+
+  finishTest();
+  yield undefined;
+}
+