diff --git a/lib/models.py b/lib/models.py
index d391be1..239f404 100644
--- a/lib/models.py
+++ b/lib/models.py
@@ -108,7 +108,9 @@ class Subject(db.Model):
     subject = cls.get_by_key_name(name)
     if subject:
       return subject
-    return cls(key_name=name).put()
+    subject = cls(key_name=name)
+    subject.put()
+    return subject
 
   @db.transactional()
   def GetRecentMessages(self, num_messages):
diff --git a/static/cosmopolite.js b/static/cosmopolite.js
index a86f20d..6109d85 100644
--- a/static/cosmopolite.js
+++ b/static/cosmopolite.js
@@ -38,6 +38,8 @@ Cosmopolite = function(callbacks, urlPrefix, namespace) {
   this.urlPrefix_ = urlPrefix || '/cosmopolite';
   this.namespace_ = namespace || 'cosmopolite';
 
+  this.shutdown_ = false;
+
   this.subscriptions_ = {};
 
   var scriptUrls = [
@@ -53,6 +55,18 @@ Cosmopolite = function(callbacks, urlPrefix, namespace) {
   }, this);
 };
 
+Cosmopolite.prototype.shutdown = function() {
+  this.shutdown_ = true;
+  if (this.socket_) {
+    var socket = this.socket_;
+    this.socket_ = null;
+    socket.close();
+  }
+  if (this.$) {
+    this.$('window').off('message');
+  }
+};
+
 /**
  * Subscribe to a subject.
  *
@@ -141,8 +155,15 @@ Cosmopolite.prototype.onLoad_ = function() {
     return;
   }
   this.$ = jQuery.noConflict(true);
+  if (this.shutdown_) {
+    // Shutdown during startup
+    return;
+  }
   this.registerMessageHandlers_();
   this.createChannel_();
+  if ('onReady' in this.callbacks_) {
+    this.callbacks_['onReady']();
+  };
 };
 
 /**
@@ -153,13 +174,13 @@ Cosmopolite.prototype.onLoad_ = function() {
 Cosmopolite.prototype.onReceiveMessage_ = function(data) {
   switch (data) {
     case 'login_complete':
-      this.socket.close();
+      this.socket_.close();
       break;
     case 'logout_complete':
       localStorage.removeItem(this.namespace_ + ':client_id');
       localStorage.removeItem(this.namespace_ + ':google_user_id');
       this.$('#google_user').empty();
-      this.socket.close();
+      this.socket_.close();
       break;
     default:
       console.log('Unknown event type:', data);
@@ -311,9 +332,12 @@ Cosmopolite.prototype.createChannel_ = function() {
  * @param {!Object} data Server response including channel token
  */
 Cosmopolite.prototype.onCreateChannel_ = function(data) {
+  if (this.shutdown_) {
+    return;
+  }
   var channel = new goog.appengine.Channel(data['token']);
   console.log('Opening channel...');
-  this.socket = channel.open({
+  this.socket_ = channel.open({
     onopen: this.$.proxy(this.onSocketOpen_, this),
     onclose: this.$.proxy(this.onSocketClose_, this),
     onmessage: this.$.proxy(this.onSocketMessage_, this),
@@ -332,11 +356,11 @@ Cosmopolite.prototype.onSocketOpen_ = function() {
  * Callback from channel library for closure; reopen.
  */
 Cosmopolite.prototype.onSocketClose_ = function() {
-  if (!this.socket) {
+  if (!this.socket_) {
     return;
   }
   console.log('Channel closed');
-  this.socket = null;
+  this.socket_ = null;
   this.createChannel_();
 };
 
@@ -405,7 +429,7 @@ Cosmopolite.prototype.onServerEvent_ = function(e) {
  */
 Cosmopolite.prototype.onSocketError_ = function(msg) {
   console.log('Socket error:', msg);
-  this.socket.close();
+  this.socket_.close();
 };
 
 /* Exported values */
diff --git a/static/debug.html b/static/debug.html
index 743efb2..ddd5f9f 100644
--- a/static/debug.html
+++ b/static/debug.html
@@ -1,6 +1,6 @@
 <html>
   <head>
-    <script type="text/javascript" src="/cosmopolite/static/cosmopolite.js" charset="UTF-8"></script>
+    <script src="/cosmopolite/static/cosmopolite.js" charset="UTF-8"></script>
     <style>
 a {
   text-decoration: none;
diff --git a/static/test.html b/static/test.html
new file mode 100644
index 0000000..f3b43fc
--- /dev/null
+++ b/static/test.html
@@ -0,0 +1,88 @@
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Cosmopolite tests</title>
+  <link rel="stylesheet" href="https://code.jquery.com/qunit/qunit-git.css">
+</head>
+<body>
+  <div id="qunit"></div>
+  <div id="qunit-fixture"></div>
+  <script src="https://code.jquery.com/qunit/qunit-git.js"></script>
+  <script src="/cosmopolite/static/cosmopolite.js" charset="UTF-8"></script>
+  <script>
+
+QUnit.begin(localStorage.clear.bind(localStorage));
+QUnit.done(localStorage.clear.bind(localStorage));
+
+var randstring = function() {
+  var ret = [];
+  for (var i = 0; i < 16; i++) {
+    var ran = (Math.random() * 16) | 0;
+    ret.push(ran.toString(16));
+  }
+  return ret.join('');
+};
+
+test('Construct/shutdown', function() {
+  expect(2);
+  var cosmo = new Cosmopolite({});
+  ok(true, 'new Cosmopolite() succeeds');
+  cosmo.shutdown();
+  ok(true, 'shutdown() succeeds');
+});
+
+asyncTest('onLogin or onLogout', function() {
+  expect(1);
+  var callbacks = {
+    'onLogin': function(user, logout_url) {
+      ok(true, 'onLogin fired');
+      cosmo.shutdown();
+      start();
+    },
+    'onLogout': function(login_url) {
+      ok(true, 'onLogout fired');
+      cosmo.shutdown();
+      start();
+    }
+  };
+  var cosmo = new Cosmopolite(callbacks);
+});
+
+asyncTest('Message round trip', function() {
+  expect(2);
+
+  var subject = randstring();
+  var message = randstring();
+
+  console.log('subject:', subject);
+  console.log('message:', message);
+
+  var callbacks1 = {
+    'onReady': function() {
+      console.log('onReady 1');
+      cosmo1.sendMessage(subject, message);
+    },
+  };
+
+  var callbacks2 = {
+    'onReady': function() {
+      console.log('onReady 2');
+      cosmo2.subscribe(subject, -1);
+    },
+    'onMessage': function(e) {
+      console.log('onMessage');
+      equal(e['subject'], subject, 'subject matches');
+      equal(e['message'], message, 'message matches');
+      cosmo1.shutdown();
+      cosmo2.shutdown();
+      start();
+    },
+  };
+
+  var cosmo1 = new Cosmopolite(callbacks1, null, randstring());
+  var cosmo2 = new Cosmopolite(callbacks2, null, randstring());
+});
+
+  </script>
+</body>
+</html>
