diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index af896fb..ddc190c 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -26,7 +26,7 @@ jobs:
         exclude:
           # pypy3 currently fails to run on Windows
           - os: windows-latest
-            python: pypy-3.8
+            python: pypy-3.9
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
diff --git a/src/socketio/admin.py b/src/socketio/admin.py
index dc45c4b..c2d2a7c 100644
--- a/src/socketio/admin.py
+++ b/src/socketio/admin.py
@@ -63,7 +63,7 @@ class InstrumentedServer:
                     namespace=self.admin_namespace)
 
         if self.mode == 'development':
-            if not self.read_only:
+            if not self.read_only:  # pragma: no branch
                 self.sio.on('emit', self.admin_emit,
                             namespace=self.admin_namespace)
                 self.sio.on('join', self.admin_enter_room,
@@ -117,8 +117,22 @@ class InstrumentedServer:
         Socket._websocket_handler = functools.partialmethod(
             self.__class__._eio_websocket_handler, self)
 
+    def uninstrument(self):  # pragma: no cover
+        if self.mode == 'development':
+            self.sio.manager.connect = self.sio.manager.__connect
+            self.sio.manager.disconnect = self.sio.manager.__disconnect
+            self.sio.manager.enter_room = self.sio.manager.__enter_room
+            self.sio.manager.leave_room = self.sio.manager.__leave_room
+            self.sio.manager.emit = self.sio.manager.__emit
+            self.sio._handle_event_internal = self.sio.__handle_event_internal
+        self.sio.eio._ok = self.sio.eio.__ok
+
+        from engineio.socket import Socket
+        Socket.handle_post_request = Socket.__handle_post_request
+        Socket._websocket_handler = Socket.__websocket_handler
+
     def admin_connect(self, sid, environ, client_auth):
-        if self.auth != None:
+        if self.auth:
             authenticated = False
             if isinstance(self.auth, dict):
                 authenticated = client_auth == self.auth
@@ -175,8 +189,9 @@ class InstrumentedServer:
             self.sio.disconnect(sid, namespace=namespace)
 
     def shutdown(self):
-        self.stop_stats_event.set()
-        self.stats_thread.join()
+        if self.stats_task:  # pragma: no branch
+            self.stop_stats_event.set()
+            self.stats_task.join()
 
     def _connect(self, eio_sid, namespace):
         sid = self.sio.manager.__connect(eio_sid, namespace)
@@ -188,22 +203,9 @@ class InstrumentedServer:
             datetime.utcfromtimestamp(t).isoformat() + 'Z',
         ), namespace=self.admin_namespace)
 
-        def check_for_upgrade():
-            for _ in range(5):
-                self.sio.sleep(5)
-                try:
-                    if self.sio.eio._get_socket(eio_sid).upgraded:
-                        self.sio.emit('socket_updated', {
-                            'id': sid,
-                            'nsp': namespace,
-                            'transport': 'websocket',
-                        }, namespace=self.admin_namespace)
-                        break
-                except KeyError:
-                    pass
-
-        if serialized_socket['transport'] == 'polling':
-            self.sio.start_background_task(check_for_upgrade)
+        if serialized_socket['transport'] == 'polling':  # pragma: no cover
+            self.sio.start_background_task(
+                self._check_for_upgrade, eio_sid, sid, namespace)
         return sid
 
     def _disconnect(self, sid, namespace, **kwargs):
@@ -216,6 +218,20 @@ class InstrumentedServer:
         ), namespace=self.admin_namespace)
         return self.sio.manager.__disconnect(sid, namespace, **kwargs)
 
+    def _check_for_upgrade(self, eio_sid, sid, namespace):  # pragma: no cover
+        for _ in range(5):
+            self.sio.sleep(5)
+            try:
+                if self.sio.eio._get_socket(eio_sid).upgraded:
+                    self.sio.emit('socket_updated', {
+                        'id': sid,
+                        'nsp': namespace,
+                        'transport': 'websocket',
+                    }, namespace=self.admin_namespace)
+                    break
+            except KeyError:
+                pass
+
     def _enter_room(self, sid, namespace, room, eio_sid=None):
         ret = self.sio.manager.__enter_room(sid, namespace, room, eio_sid)
         if room:
@@ -245,7 +261,7 @@ class InstrumentedServer:
         if namespace != self.admin_namespace:
             event_data = [event] + list(data) if isinstance(data, tuple) \
                 else [data]
-            if not isinstance(skip_sid, list):
+            if not isinstance(skip_sid, list):  # pragma: no branch
                 skip_sid = [skip_sid]
             for sid, _ in self.sio.manager.get_participants(namespace, room):
                 if sid not in skip_sid:
@@ -328,15 +344,17 @@ class InstrumentedServer:
                 'namespaces': [{
                     'name': nsp,
                     'socketsCount': len(self.sio.manager.rooms.get(
-                        nsp, {None: []})[None])
+                        nsp, {None: []}).get(None, []))
                 } for nsp in namespaces],
             }, namespace=self.admin_namespace)
 
     def serialize_socket(self, sid, namespace, eio_sid=None):
-        if eio_sid is None:
+        if eio_sid is None:  # pragma: no cover
             eio_sid = self.sio.manager.eio_sid_from_sid(sid)
         socket = self.sio.eio._get_socket(eio_sid)
         environ = self.sio.environ.get(eio_sid, {})
+        tm = self.sio.manager._timestamps[sid] if sid in \
+            self.sio.manager._timestamps else 0
         return {
             'id': sid,
             'clientId': eio_sid,
@@ -351,9 +369,9 @@ class InstrumentedServer:
                     environ.get('QUERY_STRING', '')).items()},
                 'secure': environ.get('wsgi.url_scheme', '') == 'https',
                 'url': environ.get('PATH_INFO', ''),
-                'issued': self.sio.manager._timestamps[sid] * 1000,
-                'time': datetime.utcfromtimestamp(
-                    self.sio.manager._timestamps[sid]).isoformat() + 'Z',
+                'issued': tm * 1000,
+                'time': datetime.utcfromtimestamp(tm).isoformat() + 'Z'
+                if tm else '',
             },
             'rooms': self.sio.manager.get_rooms(sid, namespace),
         }
diff --git a/src/socketio/async_simple_client.py b/src/socketio/async_simple_client.py
index b21418a..db90784 100644
--- a/src/socketio/async_simple_client.py
+++ b/src/socketio/async_simple_client.py
@@ -23,7 +23,8 @@ class AsyncSimpleClient:
         self.input_buffer = []
 
     async def connect(self, url, headers={}, auth=None, transports=None,
-                      namespace='/', socketio_path='socket.io'):
+                      namespace='/', socketio_path='socket.io',
+                      wait_timeout=5):
         """Connect to a Socket.IO server.
 
         :param url: The URL of the Socket.IO server. It can include custom
@@ -49,6 +50,8 @@ class AsyncSimpleClient:
         :param socketio_path: The endpoint where the Socket.IO server is
                               installed. The default value is appropriate for
                               most cases.
+        :param wait_timeout: How long the client should wait for the
+                             connection. The default is 5 seconds.
 
         Note: this method is a coroutine.
         """
@@ -80,7 +83,8 @@ class AsyncSimpleClient:
 
         await self.client.connect(
             url, headers=headers, auth=auth, transports=transports,
-            namespaces=[namespace], socketio_path=socketio_path)
+            namespaces=[namespace], socketio_path=socketio_path,
+            wait_timeout=wait_timeout)
 
     @property
     def sid(self):
@@ -89,7 +93,7 @@ class AsyncSimpleClient:
         The session ID is not guaranteed to remain constant throughout the life
         of the connection, as reconnections can cause it to change.
         """
-        return self.client.sid if self.client else None
+        return self.client.get_sid(self.namespace) if self.client else None
 
     @property
     def transport(self):
diff --git a/src/socketio/asyncio_admin.py b/src/socketio/asyncio_admin.py
index b491e34..3199e10 100644
--- a/src/socketio/asyncio_admin.py
+++ b/src/socketio/asyncio_admin.py
@@ -44,7 +44,7 @@ class InstrumentedAsyncServer:
                     namespace=self.admin_namespace)
 
         if self.mode == 'development':
-            if not self.read_only:
+            if not self.read_only:  # pragma: no branch
                 self.sio.on('emit', self.admin_emit,
                             namespace=self.admin_namespace)
                 self.sio.on('join', self.admin_enter_room,
@@ -89,7 +89,8 @@ class InstrumentedAsyncServer:
         from engineio.asyncio_socket import AsyncSocket
         self.sio.eio.__ok = self.sio.eio._ok
         self.sio.eio._ok = self._eio_http_response
-        AsyncSocket.__handle_post_request = functools.partialmethod(
+        AsyncSocket.__handle_post_request = AsyncSocket.handle_post_request
+        AsyncSocket.handle_post_request = functools.partialmethod(
             self.__class__._eio_handle_post_request, self)
 
         # report websocket packets
@@ -97,9 +98,23 @@ class InstrumentedAsyncServer:
         AsyncSocket._websocket_handler = functools.partialmethod(
             self.__class__._eio_websocket_handler, self)
 
+    def uninstrument(self):  # pragma: no cover
+        if self.mode == 'development':
+            self.sio.manager.connect = self.sio.manager.__connect
+            self.sio.manager.disconnect = self.sio.manager.__disconnect
+            self.sio.manager.enter_room = self.sio.manager.__enter_room
+            self.sio.manager.leave_room = self.sio.manager.__leave_room
+            self.sio.manager.emit = self.sio.manager.__emit
+            self.sio._handle_event_internal = self.sio.__handle_event_internal
+        self.sio.eio._ok = self.sio.eio.__ok
+
+        from engineio.asyncio_socket import AsyncSocket
+        AsyncSocket.handle_post_request = AsyncSocket.__handle_post_request
+        AsyncSocket._websocket_handler = AsyncSocket.__websocket_handler
+
     async def admin_connect(self, sid, environ, client_auth):
         authenticated = True
-        if self.auth != None:
+        if self.auth:
             authenticated = False
             if isinstance(self.auth, dict):
                 authenticated = client_auth == self.auth
@@ -159,8 +174,9 @@ class InstrumentedAsyncServer:
             await self.sio.disconnect(sid, namespace=namespace)
 
     async def shutdown(self):
-        self.stop_stats_event.set()
-        await asyncio.gather(self.stats_task)
+        if self.stats_task:  # pragma: no branch
+            self.stop_stats_event.set()
+            await asyncio.gather(self.stats_task)
 
     async def _connect(self, eio_sid, namespace):
         sid = await self.sio.manager.__connect(eio_sid, namespace)
@@ -172,22 +188,9 @@ class InstrumentedAsyncServer:
             datetime.utcfromtimestamp(t).isoformat() + 'Z',
         ), namespace=self.admin_namespace)
 
-        async def check_for_upgrade():
-            for _ in range(5):
-                await self.sio.sleep(5)
-                try:
-                    if self.sio.eio._get_socket(eio_sid).upgraded:
-                        await self.sio.emit('socket_updated', {
-                            'id': sid,
-                            'nsp': namespace,
-                            'transport': 'websocket',
-                        }, namespace=self.admin_namespace)
-                        break
-                except KeyError:
-                    pass
-
         if serialized_socket['transport'] == 'polling':
-            self.sio.start_background_task(check_for_upgrade)
+            self.sio.start_background_task(
+                self._check_for_upgrade, eio_sid, sid, namespace)
         return sid
 
     async def _disconnect(self, sid, namespace, **kwargs):
@@ -200,6 +203,21 @@ class InstrumentedAsyncServer:
         ), namespace=self.admin_namespace)
         return await self.sio.manager.__disconnect(sid, namespace, **kwargs)
 
+    async def _check_for_upgrade(self, eio_sid, sid,
+                                 namespace):  # pragma: no cover
+        for _ in range(5):
+            await self.sio.sleep(5)
+            try:
+                if self.sio.eio._get_socket(eio_sid).upgraded:
+                    await self.sio.emit('socket_updated', {
+                        'id': sid,
+                        'nsp': namespace,
+                        'transport': 'websocket',
+                    }, namespace=self.admin_namespace)
+                    break
+            except KeyError:
+                pass
+
     def _enter_room(self, sid, namespace, room, eio_sid=None):
         ret = self.sio.manager.__enter_room(sid, namespace, room, eio_sid)
         if room:
@@ -223,13 +241,13 @@ class InstrumentedAsyncServer:
 
     async def _emit(self, event, data, namespace, room=None, skip_sid=None,
                     callback=None, **kwargs):
-        ret = await self.sio.manager.__emit(event, data, namespace, room=room,
-                                    skip_sid=skip_sid, callback=callback,
-                                    **kwargs)
+        ret = await self.sio.manager.__emit(
+            event, data, namespace, room=room, skip_sid=skip_sid,
+            callback=callback, **kwargs)
         if namespace != self.admin_namespace:
             event_data = [event] + list(data) if isinstance(data, tuple) \
                 else [data]
-            if not isinstance(skip_sid, list):
+            if not isinstance(skip_sid, list):  # pragma: no branch
                 skip_sid = [skip_sid]
             for sid, _ in self.sio.manager.get_participants(namespace, room):
                 if sid not in skip_sid:
@@ -312,7 +330,7 @@ class InstrumentedAsyncServer:
                 'namespaces': [{
                     'name': nsp,
                     'socketsCount': len(self.sio.manager.rooms.get(
-                        nsp, {None: []})[None])
+                        nsp, {None: []}).get(None, []))
                 } for nsp in namespaces],
             }, namespace=self.admin_namespace)
             while self.admin_queue:
@@ -321,10 +339,12 @@ class InstrumentedAsyncServer:
                                     namespace=self.admin_namespace)
 
     def serialize_socket(self, sid, namespace, eio_sid=None):
-        if eio_sid is None:
+        if eio_sid is None:  # pragma: no cover
             eio_sid = self.sio.manager.eio_sid_from_sid(sid)
         socket = self.sio.eio._get_socket(eio_sid)
         environ = self.sio.environ.get(eio_sid, {})
+        tm = self.sio.manager._timestamps[sid] if sid in \
+            self.sio.manager._timestamps else 0
         return {
             'id': sid,
             'clientId': eio_sid,
@@ -339,9 +359,9 @@ class InstrumentedAsyncServer:
                     environ.get('QUERY_STRING', '')).items()},
                 'secure': environ.get('wsgi.url_scheme', '') == 'https',
                 'url': environ.get('PATH_INFO', ''),
-                'issued': self.sio.manager._timestamps[sid] * 1000,
-                'time': datetime.utcfromtimestamp(
-                    self.sio.manager._timestamps[sid]).isoformat() + 'Z',
+                'issued': tm * 1000,
+                'time': datetime.utcfromtimestamp(tm).isoformat() + 'Z'
+                if tm else '',
             },
             'rooms': self.sio.manager.get_rooms(sid, namespace),
         }
diff --git a/src/socketio/base_manager.py b/src/socketio/base_manager.py
index 6e145a1..d1b0a08 100644
--- a/src/socketio/base_manager.py
+++ b/src/socketio/base_manager.py
@@ -30,7 +30,7 @@ class BaseManager:
 
     def get_participants(self, namespace, room):
         """Return an iterable with the active participants in a room."""
-        ns = self.rooms[namespace]
+        ns = self.rooms.get(namespace, {})
         if hasattr(room, '__len__') and not isinstance(room, str):
             participants = ns[room[0]]._fwdm.copy() if room[0] in ns else {}
             for r in room[1:]:
diff --git a/src/socketio/simple_client.py b/src/socketio/simple_client.py
index 4a88380..ce3a1c5 100644
--- a/src/socketio/simple_client.py
+++ b/src/socketio/simple_client.py
@@ -23,7 +23,7 @@ class SimpleClient:
         self.input_buffer = []
 
     def connect(self, url, headers={}, auth=None, transports=None,
-                namespace='/', socketio_path='socket.io'):
+                namespace='/', socketio_path='socket.io', wait_timeout=5):
         """Connect to a Socket.IO server.
 
         :param url: The URL of the Socket.IO server. It can include custom
@@ -49,6 +49,9 @@ class SimpleClient:
         :param socketio_path: The endpoint where the Socket.IO server is
                               installed. The default value is appropriate for
                               most cases.
+        :param wait_timeout: How long the client should wait for the
+                             connection to be established. The default is 5
+                             seconds.
         """
         if self.connected:
             raise RuntimeError('Already connected')
@@ -78,7 +81,8 @@ class SimpleClient:
 
         self.client.connect(url, headers=headers, auth=auth,
                             transports=transports, namespaces=[namespace],
-                            socketio_path=socketio_path)
+                            socketio_path=socketio_path,
+                            wait_timeout=wait_timeout)
 
     @property
     def sid(self):
@@ -87,7 +91,7 @@ class SimpleClient:
         The session ID is not guaranteed to remain constant throughout the life
         of the connection, as reconnections can cause it to change.
         """
-        return self.client.sid if self.client else None
+        return self.client.get_sid(self.namespace) if self.client else None
 
     @property
     def transport(self):
diff --git a/tests/async/test_asyncio_admin.py b/tests/async/test_asyncio_admin.py
new file mode 100644
index 0000000..aaad2cf
--- /dev/null
+++ b/tests/async/test_asyncio_admin.py
@@ -0,0 +1,299 @@
+from functools import wraps
+import threading
+import time
+from unittest import mock
+import unittest
+import pytest
+from engineio.asyncio_socket import AsyncSocket as EngineIOSocket
+import socketio
+from socketio.exceptions import ConnectionError
+from tests.asyncio_web_server import SocketIOWebServer
+from .helpers import AsyncMock
+
+
+def with_instrumented_server(auth=False, **ikwargs):
+    """This decorator can be applied to test functions or methods so that they
+    run with a Socket.IO server that has been instrumented for the official
+    Admin UI project. The arguments passed to the decorator are passed directly
+    to the ``instrument()`` method of the server.
+    """
+    def decorator(f):
+        @wraps(f)
+        def wrapped(self, *args, **kwargs):
+            sio = socketio.AsyncServer(async_mode='asgi')
+            instrumented_server = sio.instrument(auth=auth, **ikwargs)
+
+            @sio.event
+            def enter_room(sid, data):
+                sio.enter_room(sid, data)
+
+            @sio.event
+            async def emit(sid, event):
+                await sio.emit(event, skip_sid=sid)
+
+            @sio.event(namespace='/foo')
+            def connect(sid, environ, auth):
+                pass
+
+            async def shutdown():
+                await instrumented_server.shutdown()
+                await sio.shutdown()
+
+            server = SocketIOWebServer(sio, on_shutdown=shutdown)
+            server.start()
+
+            # import logging
+            # logging.getLogger('engineio.client').setLevel(logging.DEBUG)
+            # logging.getLogger('socketio.client').setLevel(logging.DEBUG)
+
+            original_schedule_ping = EngineIOSocket.schedule_ping
+            EngineIOSocket.schedule_ping = mock.MagicMock()
+
+            try:
+                ret = f(self, instrumented_server, *args, **kwargs)
+            finally:
+                server.stop()
+                instrumented_server.uninstrument()
+
+            EngineIOSocket.schedule_ping = original_schedule_ping
+
+            # import logging
+            # logging.getLogger('engineio.client').setLevel(logging.NOTSET)
+            # logging.getLogger('socketio.client').setLevel(logging.NOTSET)
+
+            return ret
+        return wrapped
+    return decorator
+
+
+def _custom_auth(auth):
+    return auth == {'foo': 'bar'}
+
+
+async def _async_custom_auth(auth):
+    return auth == {'foo': 'bar'}
+
+
+class TestAsyncAdmin(unittest.TestCase):
+    def setUp(self):
+        print('threads at start:', threading.enumerate())
+        self.thread_count = threading.active_count()
+
+    def tearDown(self):
+        print('threads at end:', threading.enumerate())
+        assert self.thread_count == threading.active_count()
+
+    def test_missing_auth(self):
+        sio = socketio.AsyncServer(async_mode='asgi')
+        with pytest.raises(ValueError):
+            sio.instrument()
+
+    @with_instrumented_server(auth=False)
+    def test_admin_connect_with_no_auth(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin')
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin',
+                                 auth={'foo': 'bar'})
+
+    @with_instrumented_server(auth={'foo': 'bar'})
+    def test_admin_connect_with_dict_auth(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin',
+                                 auth={'foo': 'bar'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect(
+                    'http://localhost:8900', namespace='/admin',
+                    auth={'foo': 'baz'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect(
+                    'http://localhost:8900', namespace='/admin')
+
+    @with_instrumented_server(auth=[{'foo': 'bar'},
+                                    {'u': 'admin', 'p': 'secret'}])
+    def test_admin_connect_with_list_auth(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin',
+                                 auth={'foo': 'bar'})
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin',
+                                 auth={'u': 'admin', 'p': 'secret'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect('http://localhost:8900',
+                                     namespace='/admin', auth={'foo': 'baz'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect('http://localhost:8900',
+                                     namespace='/admin')
+
+    @with_instrumented_server(auth=_custom_auth)
+    def test_admin_connect_with_function_auth(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin',
+                                 auth={'foo': 'bar'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect('http://localhost:8900',
+                                     namespace='/admin', auth={'foo': 'baz'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect('http://localhost:8900',
+                                     namespace='/admin')
+
+    @with_instrumented_server(auth=_async_custom_auth)
+    def test_admin_connect_with_async_function_auth(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin',
+                                 auth={'foo': 'bar'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect('http://localhost:8900',
+                                     namespace='/admin', auth={'foo': 'baz'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect('http://localhost:8900',
+                                     namespace='/admin')
+
+    @with_instrumented_server()
+    def test_admin_connect_only_admin(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin')
+            sid = admin_client.sid
+            expected = ['config', 'all_sockets', 'server_stats']
+            events = {}
+            while expected:
+                data = admin_client.receive(timeout=5)
+                if data[0] in expected:
+                    events[data[0]] = data[1]
+                    expected.remove(data[0])
+
+        assert 'supportedFeatures' in events['config']
+        assert 'ALL_EVENTS' in events['config']['supportedFeatures']
+        assert len(events['all_sockets']) == 1
+        assert events['all_sockets'][0]['id'] == sid
+        assert events['all_sockets'][0]['rooms'] == [sid]
+        assert events['server_stats']['clientsCount'] == 1
+        assert events['server_stats']['pollingClientsCount'] == 0
+        assert len(events['server_stats']['namespaces']) == 3
+        assert {'name': '/', 'socketsCount': 0} in \
+            events['server_stats']['namespaces']
+        assert {'name': '/foo', 'socketsCount': 0} in \
+            events['server_stats']['namespaces']
+        assert {'name': '/admin', 'socketsCount': 1} in \
+            events['server_stats']['namespaces']
+
+    @with_instrumented_server()
+    def test_admin_connect_with_others(self, isvr):
+        with socketio.SimpleClient() as client1, \
+                socketio.SimpleClient() as client2, \
+                socketio.SimpleClient() as client3, \
+                socketio.SimpleClient() as admin_client:
+            client1.connect('http://localhost:8900')
+            client1.emit('enter_room', 'room')
+            sid1 = client1.sid
+
+            saved_check_for_upgrade = isvr._check_for_upgrade
+            isvr._check_for_upgrade = AsyncMock()
+            client2.connect('http://localhost:8900', namespace='/foo',
+                            transports=['polling'])
+            sid2 = client2.sid
+            isvr._check_for_upgrade = saved_check_for_upgrade
+
+            client3.connect('http://localhost:8900', namespace='/admin')
+            sid3 = client3.sid
+
+            admin_client.connect('http://localhost:8900', namespace='/admin')
+            sid = admin_client.sid
+            expected = ['config', 'all_sockets', 'server_stats']
+            events = {}
+            while expected:
+                data = admin_client.receive(timeout=5)
+                if data[0] in expected:
+                    events[data[0]] = data[1]
+                    expected.remove(data[0])
+
+        assert 'supportedFeatures' in events['config']
+        assert 'ALL_EVENTS' in events['config']['supportedFeatures']
+        assert len(events['all_sockets']) == 4
+        assert events['server_stats']['clientsCount'] == 4
+        assert events['server_stats']['pollingClientsCount'] == 1
+        assert len(events['server_stats']['namespaces']) == 3
+        assert {'name': '/', 'socketsCount': 1} in \
+            events['server_stats']['namespaces']
+        assert {'name': '/foo', 'socketsCount': 1} in \
+            events['server_stats']['namespaces']
+        assert {'name': '/admin', 'socketsCount': 2} in \
+            events['server_stats']['namespaces']
+
+        for socket in events['all_sockets']:
+            if socket['id'] == sid:
+                assert socket['rooms'] == [sid]
+            elif socket['id'] == sid1:
+                assert socket['rooms'] == [sid1, 'room']
+            elif socket['id'] == sid2:
+                assert socket['rooms'] == [sid2]
+            elif socket['id'] == sid3:
+                assert socket['rooms'] == [sid3]
+
+    @with_instrumented_server(mode='production')
+    def test_admin_connect_production(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin')
+            expected = ['config', 'server_stats']
+            events = {}
+            while expected:
+                data = admin_client.receive(timeout=5)
+                if data[0] in expected:
+                    events[data[0]] = data[1]
+                    expected.remove(data[0])
+
+        assert 'supportedFeatures' in events['config']
+        assert 'ALL_EVENTS' not in events['config']['supportedFeatures']
+        assert events['server_stats']['clientsCount'] == 1
+        assert events['server_stats']['pollingClientsCount'] == 0
+        assert len(events['server_stats']['namespaces']) == 3
+        assert {'name': '/', 'socketsCount': 0} in \
+            events['server_stats']['namespaces']
+        assert {'name': '/foo', 'socketsCount': 0} in \
+            events['server_stats']['namespaces']
+        assert {'name': '/admin', 'socketsCount': 1} in \
+            events['server_stats']['namespaces']
+
+    @with_instrumented_server()
+    def test_admin_features(self, isvr):
+        with socketio.SimpleClient() as client1, \
+                socketio.SimpleClient() as client2, \
+                socketio.SimpleClient() as admin_client:
+            client1.connect('http://localhost:8900')
+            client2.connect('http://localhost:8900')
+            admin_client.connect('http://localhost:8900', namespace='/admin')
+
+            # emit from admin
+            admin_client.emit(
+                'emit', ('/', client1.sid, 'foo', {'bar': 'baz'}, 'extra'))
+            data = client1.receive(timeout=5)
+            assert data == ['foo', {'bar': 'baz'}, 'extra']
+
+            # emit from regular client
+            client1.emit('emit', 'foo')
+            data = client2.receive(timeout=5)
+            assert data == ['foo']
+
+            # join and leave
+            admin_client.emit('join', ('/', 'room', client1.sid))
+            admin_client.emit(
+                'emit', ('/', 'room', 'foo', {'bar': 'baz'}))
+            data = client1.receive(timeout=5)
+            assert data == ['foo', {'bar': 'baz'}]
+            admin_client.emit('leave', ('/', 'room'))
+
+            # disconnect
+            admin_client.emit('_disconnect', ('/', False, client1.sid))
+            for _ in range(10):
+                if not client1.connected:
+                    break
+                time.sleep(0.2)
+            assert not client1.connected
diff --git a/tests/async/test_manager.py b/tests/async/test_manager.py
index 306734d..0b2fc93 100644
--- a/tests/async/test_manager.py
+++ b/tests/async/test_manager.py
@@ -353,7 +353,7 @@ class TestAsyncManager(unittest.TestCase):
         _run(self.bm.emit('my event', {'foo': 'bar'}, namespace='/foo'))
 
     def test_emit_with_tuple(self):
-        sid = self.bm.connect('123', '/foo')
+        sid = _run(self.bm.connect('123', '/foo'))
         _run(
             self.bm.emit(
                 'my event', ('foo', 'bar'), namespace='/foo', room=sid
@@ -366,7 +366,7 @@ class TestAsyncManager(unittest.TestCase):
         assert pkt.encode() == '42/foo,["my event","foo","bar"]'
 
     def test_emit_with_list(self):
-        sid = self.bm.connect('123', '/foo')
+        sid = _run(self.bm.connect('123', '/foo'))
         _run(
             self.bm.emit(
                 'my event', ['foo', 'bar'], namespace='/foo', room=sid
@@ -379,7 +379,7 @@ class TestAsyncManager(unittest.TestCase):
         assert pkt.encode() == '42/foo,["my event",["foo","bar"]]'
 
     def test_emit_with_none(self):
-        sid = self.bm.connect('123', '/foo')
+        sid = _run(self.bm.connect('123', '/foo'))
         _run(
             self.bm.emit(
                 'my event', None, namespace='/foo', room=sid
@@ -392,7 +392,7 @@ class TestAsyncManager(unittest.TestCase):
         assert pkt.encode() == '42/foo,["my event"]'
 
     def test_emit_binary(self):
-        sid = self.bm.connect('123', '/')
+        sid = _run(self.bm.connect('123', '/'))
         _run(
             self.bm.emit(
                 u'my event', b'my binary data', namespace='/', room=sid
diff --git a/tests/async/test_simple_client.py b/tests/async/test_simple_client.py
index 397ae98..f8996bd 100644
--- a/tests/async/test_simple_client.py
+++ b/tests/async/test_simple_client.py
@@ -24,12 +24,13 @@ class TestAsyncAsyncSimpleClient(unittest.TestCase):
             mock_client.return_value.connect = AsyncMock()
 
             _run(client.connect('url', headers='h', auth='a', transports='t',
-                                namespace='n', socketio_path='s'))
+                                namespace='n', socketio_path='s',
+                                wait_timeout='w'))
             mock_client.assert_called_once_with(123, a='b')
             assert client.client == mock_client()
             mock_client().connect.mock.assert_called_once_with(
                 'url', headers='h', auth='a', transports='t',
-                namespaces=['n'], socketio_path='s')
+                namespaces=['n'], socketio_path='s', wait_timeout='w')
             mock_client().event.call_count == 3
             mock_client().on.called_once_with('*')
             assert client.namespace == 'n'
@@ -44,12 +45,12 @@ class TestAsyncAsyncSimpleClient(unittest.TestCase):
 
                     await client.connect('url', headers='h', auth='a',
                                          transports='t', namespace='n',
-                                         socketio_path='s')
+                                         socketio_path='s', wait_timeout='w')
                     mock_client.assert_called_once_with(123, a='b')
                     assert client.client == mock_client()
                     mock_client().connect.mock.assert_called_once_with(
                         'url', headers='h', auth='a', transports='t',
-                        namespaces=['n'], socketio_path='s')
+                        namespaces=['n'], socketio_path='s', wait_timeout='w')
                     mock_client().event.call_count == 3
                     mock_client().on.called_once_with('*')
                     assert client.namespace == 'n'
@@ -67,7 +68,8 @@ class TestAsyncAsyncSimpleClient(unittest.TestCase):
 
     def test_properties(self):
         client = AsyncSimpleClient()
-        client.client = mock.MagicMock(sid='sid', transport='websocket')
+        client.client = mock.MagicMock(transport='websocket')
+        client.client.get_sid.return_value = 'sid'
         client.connected_event.set()
         client.connected = True
 
diff --git a/tests/asyncio_web_server.py b/tests/asyncio_web_server.py
new file mode 100644
index 0000000..8b2046c
--- /dev/null
+++ b/tests/asyncio_web_server.py
@@ -0,0 +1,57 @@
+import requests
+import threading
+import time
+import uvicorn
+import socketio
+
+
+class SocketIOWebServer:
+    """A simple web server used for running Socket.IO servers in tests.
+
+    :param sio: a Socket.IO server instance.
+
+    Note 1: This class is not production-ready and is intended for testing.
+    Note 2: This class only supports the "asgi" async_mode.
+    """
+    def __init__(self, sio, on_shutdown=None):
+        if sio.async_mode != 'asgi':
+            raise ValueError('The async_mode must be "asgi"')
+
+        async def http_app(scope, receive, send):
+            await send({'type': 'http.response.start',
+                        'status': 200,
+                        'headers': [('Content-Type', 'text/plain')]})
+            await send({'type': 'http.response.body',
+                        'body': b'OK'})
+
+        self.sio = sio
+        self.app = socketio.ASGIApp(sio, http_app, on_shutdown=on_shutdown)
+        self.httpd = None
+        self.thread = None
+
+    def start(self, port=8900):
+        """Start the web server.
+
+        :param port: the port to listen on. Defaults to 8900.
+
+        The server is started in a background thread.
+        """
+        self.httpd = uvicorn.Server(config=uvicorn.Config(self.app, port=port))
+        self.thread = threading.Thread(target=self.httpd.run)
+        self.thread.start()
+
+        # wait for the server to start
+        while True:
+            try:
+                r = requests.get(f'http://localhost:{port}/')
+                r.raise_for_status()
+                if r.text == 'OK':
+                    break
+            except:
+                time.sleep(0.1)
+
+    def stop(self):
+        """Stop the web server."""
+        self.httpd.should_exit = True
+        self.thread.join()
+        self.thread = None
diff --git a/tests/common/test_admin.py b/tests/common/test_admin.py
new file mode 100644
index 0000000..658d3a3
--- /dev/null
+++ b/tests/common/test_admin.py
@@ -0,0 +1,277 @@
+from functools import wraps
+import threading
+import time
+from unittest import mock
+import unittest
+import pytest
+from engineio.socket import Socket as EngineIOSocket
+import socketio
+from socketio.exceptions import ConnectionError
+from tests.web_server import SocketIOWebServer
+
+
+def with_instrumented_server(auth=False, **ikwargs):
+    """This decorator can be applied to test functions or methods so that they
+    run with a Socket.IO server that has been instrumented for the official
+    Admin UI project. The arguments passed to the decorator are passed directly
+    to the ``instrument()`` method of the server.
+    """
+    def decorator(f):
+        @wraps(f)
+        def wrapped(self, *args, **kwargs):
+            sio = socketio.Server(async_mode='threading')
+            instrumented_server = sio.instrument(auth=auth, **ikwargs)
+
+            @sio.event
+            def enter_room(sid, data):
+                sio.enter_room(sid, data)
+
+            @sio.event
+            def emit(sid, event):
+                sio.emit(event, skip_sid=sid)
+
+            @sio.event(namespace='/foo')
+            def connect(sid, environ, auth):
+                pass
+
+            server = SocketIOWebServer(sio)
+            server.start()
+
+            # import logging
+            # logging.getLogger('engineio.client').setLevel(logging.DEBUG)
+            # logging.getLogger('socketio.client').setLevel(logging.DEBUG)
+
+            original_schedule_ping = EngineIOSocket.schedule_ping
+            EngineIOSocket.schedule_ping = mock.MagicMock()
+
+            try:
+                ret = f(self, instrumented_server, *args, **kwargs)
+            finally:
+                server.stop()
+                instrumented_server.shutdown()
+                instrumented_server.uninstrument()
+
+            EngineIOSocket.schedule_ping = original_schedule_ping
+
+            # import logging
+            # logging.getLogger('engineio.client').setLevel(logging.NOTSET)
+            # logging.getLogger('socketio.client').setLevel(logging.NOTSET)
+
+            return ret
+        return wrapped
+    return decorator
+
+
+def _custom_auth(auth):
+    return auth == {'foo': 'bar'}
+
+
+class TestAdmin(unittest.TestCase):
+    def setUp(self):
+        print('threads at start:', threading.enumerate())
+        self.thread_count = threading.active_count()
+
+    def tearDown(self):
+        print('threads at end:', threading.enumerate())
+        assert self.thread_count == threading.active_count()
+
+    def test_missing_auth(self):
+        sio = socketio.Server(async_mode='threading')
+        with pytest.raises(ValueError):
+            sio.instrument()
+
+    @with_instrumented_server(auth=False)
+    def test_admin_connect_with_no_auth(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin')
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin',
+                                 auth={'foo': 'bar'})
+
+    @with_instrumented_server(auth={'foo': 'bar'})
+    def test_admin_connect_with_dict_auth(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin',
+                                 auth={'foo': 'bar'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect(
+                    'http://localhost:8900', namespace='/admin',
+                    auth={'foo': 'baz'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect(
+                    'http://localhost:8900', namespace='/admin')
+
+    @with_instrumented_server(auth=[{'foo': 'bar'},
+                                    {'u': 'admin', 'p': 'secret'}])
+    def test_admin_connect_with_list_auth(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin',
+                                 auth={'foo': 'bar'})
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin',
+                                 auth={'u': 'admin', 'p': 'secret'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect('http://localhost:8900',
+                                     namespace='/admin', auth={'foo': 'baz'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect('http://localhost:8900',
+                                     namespace='/admin')
+
+    @with_instrumented_server(auth=_custom_auth)
+    def test_admin_connect_with_function_auth(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin',
+                                 auth={'foo': 'bar'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect('http://localhost:8900',
+                                     namespace='/admin', auth={'foo': 'baz'})
+        with socketio.SimpleClient() as admin_client:
+            with pytest.raises(ConnectionError):
+                admin_client.connect('http://localhost:8900',
+                                     namespace='/admin')
+
+    @with_instrumented_server()
+    def test_admin_connect_only_admin(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin')
+            sid = admin_client.sid
+            expected = ['config', 'all_sockets', 'server_stats']
+            events = {}
+            while expected:
+                data = admin_client.receive(timeout=5)
+                if data[0] in expected:
+                    events[data[0]] = data[1]
+                    expected.remove(data[0])
+
+        assert 'supportedFeatures' in events['config']
+        assert 'ALL_EVENTS' in events['config']['supportedFeatures']
+        assert len(events['all_sockets']) == 1
+        assert events['all_sockets'][0]['id'] == sid
+        assert events['all_sockets'][0]['rooms'] == [sid]
+        assert events['server_stats']['clientsCount'] == 1
+        assert events['server_stats']['pollingClientsCount'] == 0
+        assert len(events['server_stats']['namespaces']) == 3
+        assert {'name': '/', 'socketsCount': 0} in \
+            events['server_stats']['namespaces']
+        assert {'name': '/foo', 'socketsCount': 0} in \
+            events['server_stats']['namespaces']
+        assert {'name': '/admin', 'socketsCount': 1} in \
+            events['server_stats']['namespaces']
+
+    @with_instrumented_server()
+    def test_admin_connect_with_others(self, isvr):
+        with socketio.SimpleClient() as client1, \
+                socketio.SimpleClient() as client2, \
+                socketio.SimpleClient() as client3, \
+                socketio.SimpleClient() as admin_client:
+            client1.connect('http://localhost:8900')
+            client1.emit('enter_room', 'room')
+            sid1 = client1.sid
+
+            saved_check_for_upgrade = isvr._check_for_upgrade
+            isvr._check_for_upgrade = mock.MagicMock()
+            client2.connect('http://localhost:8900', namespace='/foo',
+                            transports=['polling'])
+            sid2 = client2.sid
+            isvr._check_for_upgrade = saved_check_for_upgrade
+
+            client3.connect('http://localhost:8900', namespace='/admin')
+            sid3 = client3.sid
+
+            admin_client.connect('http://localhost:8900', namespace='/admin')
+            sid = admin_client.sid
+            expected = ['config', 'all_sockets', 'server_stats']
+            events = {}
+            while expected:
+                data = admin_client.receive(timeout=5)
+                if data[0] in expected:
+                    events[data[0]] = data[1]
+                    expected.remove(data[0])
+
+        assert 'supportedFeatures' in events['config']
+        assert 'ALL_EVENTS' in events['config']['supportedFeatures']
+        assert len(events['all_sockets']) == 4
+        assert events['server_stats']['clientsCount'] == 4
+        assert events['server_stats']['pollingClientsCount'] == 1
+        assert len(events['server_stats']['namespaces']) == 3
+        assert {'name': '/', 'socketsCount': 1} in \
+            events['server_stats']['namespaces']
+        assert {'name': '/foo', 'socketsCount': 1} in \
+            events['server_stats']['namespaces']
+        assert {'name': '/admin', 'socketsCount': 2} in \
+            events['server_stats']['namespaces']
+
+        for socket in events['all_sockets']:
+            if socket['id'] == sid:
+                assert socket['rooms'] == [sid]
+            elif socket['id'] == sid1:
+                assert socket['rooms'] == [sid1, 'room']
+            elif socket['id'] == sid2:
+                assert socket['rooms'] == [sid2]
+            elif socket['id'] == sid3:
+                assert socket['rooms'] == [sid3]
+
+    @with_instrumented_server(mode='production')
+    def test_admin_connect_production(self, isvr):
+        with socketio.SimpleClient() as admin_client:
+            admin_client.connect('http://localhost:8900', namespace='/admin')
+            expected = ['config', 'server_stats']
+            events = {}
+            while expected:
+                data = admin_client.receive(timeout=5)
+                if data[0] in expected:
+                    events[data[0]] = data[1]
+                    expected.remove(data[0])
+
+        assert 'supportedFeatures' in events['config']
+        assert 'ALL_EVENTS' not in events['config']['supportedFeatures']
+        assert events['server_stats']['clientsCount'] == 1
+        assert events['server_stats']['pollingClientsCount'] == 0
+        assert len(events['server_stats']['namespaces']) == 3
+        assert {'name': '/', 'socketsCount': 0} in \
+            events['server_stats']['namespaces']
+        assert {'name': '/foo', 'socketsCount': 0} in \
+            events['server_stats']['namespaces']
+        assert {'name': '/admin', 'socketsCount': 1} in \
+            events['server_stats']['namespaces']
+
+    @with_instrumented_server()
+    def test_admin_features(self, isvr):
+        with socketio.SimpleClient() as client1, \
+                socketio.SimpleClient() as client2, \
+                socketio.SimpleClient() as admin_client:
+            client1.connect('http://localhost:8900')
+            client2.connect('http://localhost:8900')
+            admin_client.connect('http://localhost:8900', namespace='/admin')
+
+            # emit from admin
+            admin_client.emit(
+                'emit', ('/', client1.sid, 'foo', {'bar': 'baz'}, 'extra'))
+            data = client1.receive(timeout=5)
+            assert data == ['foo', {'bar': 'baz'}, 'extra']
+
+            # emit from regular client
+            client1.emit('emit', 'foo')
+            data = client2.receive(timeout=5)
+            assert data == ['foo']
+
+            # join and leave
+            admin_client.emit('join', ('/', 'room', client1.sid))
+            admin_client.emit(
+                'emit', ('/', 'room', 'foo', {'bar': 'baz'}))
+            data = client1.receive(timeout=5)
+            assert data == ['foo', {'bar': 'baz'}]
+            admin_client.emit('leave', ('/', 'room'))
+
+            # disconnect
+            admin_client.emit('_disconnect', ('/', False, client1.sid))
+            for _ in range(10):
+                if not client1.connected:
+                    break
+                time.sleep(0.2)
+            assert not client1.connected
diff --git a/tests/common/test_simple_client.py b/tests/common/test_simple_client.py
index 2a0b7b7..4069042 100644
--- a/tests/common/test_simple_client.py
+++ b/tests/common/test_simple_client.py
@@ -18,12 +18,12 @@ class TestSimpleClient(unittest.TestCase):
         client = SimpleClient(123, a='b')
         with mock.patch('socketio.simple_client.Client') as mock_client:
             client.connect('url', headers='h', auth='a', transports='t',
-                           namespace='n', socketio_path='s')
+                           namespace='n', socketio_path='s', wait_timeout='w')
             mock_client.assert_called_once_with(123, a='b')
             assert client.client == mock_client()
             mock_client().connect.assert_called_once_with(
                 'url', headers='h', auth='a', transports='t',
-                namespaces=['n'], socketio_path='s')
+                namespaces=['n'], socketio_path='s', wait_timeout='w')
             mock_client().event.call_count == 3
             mock_client().on.called_once_with('*')
             assert client.namespace == 'n'
@@ -33,12 +33,13 @@ class TestSimpleClient(unittest.TestCase):
         with SimpleClient(123, a='b') as client:
             with mock.patch('socketio.simple_client.Client') as mock_client:
                 client.connect('url', headers='h', auth='a', transports='t',
-                               namespace='n', socketio_path='s')
+                               namespace='n', socketio_path='s',
+                               wait_timeout='w')
                 mock_client.assert_called_once_with(123, a='b')
                 assert client.client == mock_client()
                 mock_client().connect.assert_called_once_with(
                     'url', headers='h', auth='a', transports='t',
-                    namespaces=['n'], socketio_path='s')
+                    namespaces=['n'], socketio_path='s', wait_timeout='w')
                 mock_client().event.call_count == 3
                 mock_client().on.called_once_with('*')
                 assert client.namespace == 'n'
@@ -54,7 +55,8 @@ class TestSimpleClient(unittest.TestCase):
 
     def test_properties(self):
         client = SimpleClient()
-        client.client = mock.MagicMock(sid='sid', transport='websocket')
+        client.client = mock.MagicMock(transport='websocket')
+        client.client.get_sid.return_value = 'sid'
         client.connected_event.set()
         client.connected = True
 
diff --git a/tests/web_server.py b/tests/web_server.py
new file mode 100644
index 0000000..cb24668
--- /dev/null
+++ b/tests/web_server.py
@@ -0,0 +1,81 @@
+import threading
+import time
+from socketserver import ThreadingMixIn
+from wsgiref.simple_server import make_server, WSGIServer, WSGIRequestHandler
+import requests
+import socketio
+
+
+class SocketIOWebServer:
+    """A simple web server used for running Socket.IO servers in tests.
+
+    :param sio: a Socket.IO server instance.
+
+    Note 1: This class is not production-ready and is intended for testing.
+    Note 2: This class only supports the "threading" async_mode, with WebSocket
+    support provided by the simple-websocket package.
+    """
+    def __init__(self, sio):
+        if sio.async_mode != 'threading':
+            raise ValueError('The async_mode must be "threading"')
+
+        def http_app(environ, start_response):
+            start_response('200 OK', [('Content-Type', 'text/plain')])
+            return [b'OK']
+
+        self.sio = sio
+        self.app = socketio.WSGIApp(sio, http_app)
+        self.httpd = None
+        self.thread = None
+
+    def start(self, port=8900):
+        """Start the web server.
+
+        :param port: the port to listen on. Defaults to 8900.
+
+        The server is started in a background thread.
+        """
+        class ThreadingWSGIServer(ThreadingMixIn, WSGIServer):
+            pass
+
+        class WebSocketRequestHandler(WSGIRequestHandler):
+            def get_environ(self):
+                env = super().get_environ()
+
+                # pass the raw socket to the WSGI app so that it can be used
+                # by WebSocket connections (hack copied from gunicorn)
+                env['gunicorn.socket'] = self.connection
+                return env
+
+        self.httpd = make_server('', port, self._app_wrapper,
+                                 ThreadingWSGIServer, WebSocketRequestHandler)
+        self.thread = threading.Thread(target=self.httpd.serve_forever)
+        self.thread.start()
+
+        # wait for the server to start
+        while True:
+            try:
+                r = requests.get(f'http://localhost:{port}/')
+                r.raise_for_status()
+                if r.text == 'OK':
+                    break
+            except:
+                time.sleep(0.1)
+
+    def stop(self):
+        """Stop the web server."""
+        self.sio.shutdown()
+        self.httpd.shutdown()
+        self.httpd.server_close()
+        self.thread.join()
+        self.httpd = None
+        self.thread = None
+
+    def _app_wrapper(self, environ, start_response):
+        try:
+            return self.app(environ, start_response)
+        except StopIteration:
+            # end the WebSocket request without sending a response
+            # (this is a hack that was copied from gunicorn's threaded worker)
+            start_response('200 OK', [])
+            return []
diff --git a/tox.ini b/tox.ini
index 12d2891..2929457 100644
--- a/tox.ini
+++ b/tox.ini
@@ -14,10 +14,16 @@ python =
 [testenv]
 commands=
     pip install -e .
-    pytest -p no:logging --cov=socketio --cov-branch --cov-report=term-missing --cov-report=xml
+    pytest -p no:logging --timeout=60 --cov=socketio --cov-branch --cov-report=term-missing --cov-report=xml
 deps=
+    simple-websocket
+    uvicorn
+    requests
+    websocket-client
+    aiohttp
     msgpack
     pytest
+    pytest-timeout
     pytest-cov
 
 [testenv:flake8]