# Pastebin eRspClC6
diff --git a/lib/gitter-adapter.js b/lib/gitter-adapter.js
--- a/lib/gitter-adapter.js
+++ b/lib/gitter-adapter.js
@@ -30,6 +30,9 @@ function obfuscateToken(token) {
   return repeat('*', token.length - 8) + token.slice(token.length - 8);
 }

+function nickToMask(nick) {
+  return ':' + nick + '!' + nick + '@irc.gitter.im';
+}

 var cacheDelegate = new LruCacheDelegate({
   max: 2048,
@@ -82,7 +85,7 @@ Adapter.prototype.listenForOneToOnes = f
     .then(function(room) {
       if (!room.oneToOne) return;
       var nick = room.user.username;
-      var mask = ':' + nick + '!' + nick + '@irc.gitter.im';
+      var mask = nickToMask(nick);
       msg.text.split('\n').forEach(function(line) {
         c.send(mask, 'PRIVMSG', c.nick, ':' + line);
       });
@@ -168,12 +171,37 @@ Adapter.prototype.setup = function(token
   }.bind(this));
 };

+Adapter.prototype.getOurRoom = function getOurRoom(room) {
+  var uri = room.uri.toLowerCase();
+  if (!this.rooms[uri])
+    this.rooms[uri] = room;
+  return this.rooms[uri];
+};
+
 Adapter.prototype.subscribeToRoom = function(room) {
   var self = this;
   var c = this.client;

   debug('Subscribing to room ' + room.uri, { token: this.loggableToken});

+  var ourroom = this.getOurRoom(room);
+  ourroom._users = {};
+  ourroom.hasUser = function hasUser(nick) {
+    ourroom._users[nick] = true;
+  }
+  ourroom.addUser = function addUser(nick) {
+    if (nick in ourroom._users)
+      return;
+    this.hasUser(nick);
+    c.send(nickToMask(nick), 'JOIN', '#' + room.uri);
+  }
+  ourroom.delUser = function delUser(nick) {
+    if (nick in ourroom._users) {
+      delete ourroom._users[nick];
+      c.send(nickToMask(nick), 'PART', '#' + room.uri);
+    }
+  }
+
   room.subscribe();

   room.on('chatMessages', function(evt) {
@@ -183,7 +211,9 @@ Adapter.prototype.subscribeToRoom = func
     var nick = message.fromUser.username;
     if (nick === c.nick) return; // User's own message

-    var mask = ':' + nick + '!' + nick + '@irc.gitter.im';
+    var ourroom = this.getOurRoom(room);
+    ourroom.addUser(nick);
+    var mask = nickToMask(nick);

     var text;
     message.text.split('\n').forEach(function(line) {
@@ -212,13 +242,11 @@ Adapter.prototype.subscribeToRoom = func
     var nick, mask;
     if (evt.operation === 'create') {
       nick = evt.model.username;
-      mask = ':' + nick + '!' + nick + '@irc.gitter.im';
-      c.send(mask, 'JOIN', '#' + room.uri);
+      room.addUser(nick);
     }
     if (evt.operation === 'remove') {
       nick = evt.model.username;
-      mask = ':' + nick + '!' + nick + '@irc.gitter.im';
-      c.send(mask, 'PART', '#' + room.uri);
+      room.delUser(nick);
     }
   }.bind(this));

@@ -348,7 +376,9 @@ Adapter.prototype.listUsers = function(c
   }.bind(this));

   getRoomMembers.then(function(users) {
+    var room = this.rooms[uri];
     (users || []).forEach(function(user) {
+      room.hasUser(user.username);
       c.send(c.host, irc.reply.who, c.nick, channel, user.username, c.hostname, c.hostname, user.username, 'H', ':0', user.displayName);
     });
     c.send(c.host, irc.reply.who, c.nick, channel, 'gitter', c.hostname, c.hostname, 'gitter', 'H', ':0', 'Gitter Bot');
diff --git a/test/gitter-adapter_test.js b/test/gitter-adapter_test.js
--- a/test/gitter-adapter_test.js
+++ b/test/gitter-adapter_test.js
@@ -59,4 +59,68 @@ describe('Gitter Adapter', function(){
     return adapter.sendPromiseChain;
   });

+  it('Should report users for who', function() {
+    client.authenticated = true;
+    client.nick = 'bar'; // obtained after auth
+    var spy = sinon.spy();
+    var stub = sinon.stub(socket, 'write', spy);
+    adapter.sendMessage = spy;
+    adapter.setup("fake-token");
+    var eventMap = {};
+    adapter.subscribeToRoom({
+      'uri':'hello',
+      'id':'hello-room',
+      subscribe:function(){},
+      on:function(event, cb) {
+        eventMap[event] = cb;
+      }
+    });
+    client.parse('WHO hello');
+    eventMap['users']({
+      'operation': 'create',
+      'model': {
+        'username': 'test'
+      }
+    });
+    adapter.sendPromiseChain = adapter.sendPromiseChain.then(function() {
+      assert(spy.firstCall.calledWith(':bar!bar@irc.gitter.im WHO :hello\r\n'));
+      assert(spy.secondCall.calledWith(':test!test@irc.gitter.im JOIN #hello\r\n'));
+      assert(spy.calledTwice);
+    });
+    return adapter.sendPromiseChain;
+  });
+
+  it('Should report users for messages', function() {
+    client.authenticated = true;
+    client.nick = 'bar'; // obtained after auth
+    var spy = sinon.spy();
+    var stub = sinon.stub(socket, 'write', spy);
+    adapter.sendMessage = spy;
+    adapter.setup("fake-token");
+    var eventMap = {};
+    adapter.subscribeToRoom({
+      'uri':'hello',
+      'id':'hello-room',
+      subscribe:function(){},
+      on:function(event, cb) {
+        eventMap[event] = cb;
+      }
+    });
+    eventMap['chatMessages']({
+      'operation': 'create',
+      'model': {
+        'fromUser': {
+          'username': 'test'
+        },
+        'text': 'hello',
+        'id': 1000,
+      },
+    });
+    adapter.sendPromiseChain = adapter.sendPromiseChain.then(function() {
+      assert(spy.firstCall.calledWith(':test!test@irc.gitter.im JOIN #hello\r\n'));
+      assert(spy.secondCall.calledWith(':test!test@irc.gitter.im PRIVMSG #hello :hello\r\n'));
+      assert(spy.calledTwice);
+    });
+    return adapter.sendPromiseChain;
+  });
 });