diff -r 000000000000 -r 6474c204b198 services/sync/tests/unit/test_password_store.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/services/sync/tests/unit/test_password_store.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,61 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+Cu.import("resource://services-sync/engines/passwords.js");
+Cu.import("resource://services-sync/service.js");
+Cu.import("resource://services-sync/util.js");
+
+function run_test() {
+  initTestLogging("Trace");
+  Log.repository.getLogger("Sync.Engine.Passwords").level = Log.Level.Trace;
+  Log.repository.getLogger("Sync.Store.Passwords").level = Log.Level.Trace;
+
+  const BOGUS_GUID_A = "zzzzzzzzzzzz";
+  const BOGUS_GUID_B = "yyyyyyyyyyyy";
+  let recordA = {id: BOGUS_GUID_A,
+                  hostname: "http://foo.bar.com",
+                  formSubmitURL: "http://foo.bar.com/baz",
+                  httpRealm: "secure",
+                  username: "john",
+                  password: "smith",
+                  usernameField: "username",
+                  passwordField: "password"};
+  let recordB = {id: BOGUS_GUID_B,
+                  hostname: "http://foo.baz.com",
+                  formSubmitURL: "http://foo.baz.com/baz",
+                  username: "john",
+                  password: "smith",
+                  usernameField: "username",
+                  passwordField: "password"};
+
+  let engine = Service.engineManager.get("passwords");
+  let store = engine._store;
+  function applyEnsureNoFailures(records) {
+    do_check_eq(store.applyIncomingBatch(records).length, 0);
+  }
+
+  try {
+    applyEnsureNoFailures([recordA, recordB]);
+
+    // Only the good record makes it to Services.logins.
+    let badCount = {};
+    let goodCount = {};
+    let badLogins = Services.logins.findLogins(badCount, recordA.hostname,
+                                               recordA.formSubmitURL,
+                                               recordA.httpRealm);
+    let goodLogins = Services.logins.findLogins(goodCount, recordB.hostname,
+                                                recordB.formSubmitURL, null);
+
+    _("Bad: " + JSON.stringify(badLogins));
+    _("Good: " + JSON.stringify(goodLogins));
+    _("Count: " + badCount.value + ", " + goodCount.value);
+
+    do_check_eq(goodCount.value, 1);
+    do_check_eq(badCount.value, 0);
+
+    do_check_true(!!store.getAllIDs()[BOGUS_GUID_B]);
+    do_check_true(!store.getAllIDs()[BOGUS_GUID_A]);
+  } finally {
+    store.wipe();
+  }
+}