diff -r 000000000000 -r 6474c204b198 dom/indexedDB/test/unit/test_add_twice_failure.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/indexedDB/test/unit/test_add_twice_failure.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,39 @@
+/**
+ * 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 request = indexedDB.open(name, 1);
+  request.onerror = errorHandler;
+  request.onupgradeneeded = grabEventAndContinueHandler;
+  let event = yield undefined;
+
+  let db = request.result;
+
+  ok(event.target === request, "Good event target");
+
+  let objectStore = db.createObjectStore("foo", { keyPath: null });
+  let key = 10;
+
+  request = objectStore.add({}, key);
+  request.onerror = errorHandler;
+  request.onsuccess = grabEventAndContinueHandler;
+  event = yield undefined;
+
+  is(request.result, key, "Correct key");
+
+  request = objectStore.add({}, key);
+  request.addEventListener("error", new ExpectError("ConstraintError", true));
+  request.onsuccess = unexpectedSuccessHandler;
+  yield undefined;
+
+  finishTest();
+  yield undefined;
+}
+