diff --git a/src/calibre/srv/tests/web_sockets.py b/src/calibre/srv/tests/web_sockets.py
index 63a733511a..e8e9cb8e52 100644
--- a/src/calibre/srv/tests/web_sockets.py
+++ b/src/calibre/srv/tests/web_sockets.py
@@ -16,7 +16,7 @@ from calibre.srv.web_socket import (
 from calibre.utils.monotonic import monotonic
 from calibre.utils.socket_inheritance import set_socket_inherit
 from polyglot.builtins import range, unicode_type
-from polyglot.binary import as_base64_bytes, as_base64_unicode
+from polyglot.binary import as_base64_unicode
 
 HANDSHAKE_STR = '''\
 GET / HTTP/1.1\r
@@ -35,7 +35,7 @@ class WSClient(object):
         self.timeout = timeout
         self.socket = socket.create_connection(('localhost', port), timeout)
         set_socket_inherit(self.socket, False)
-        self.key = as_base64_bytes(os.urandom(8))
+        self.key = as_base64_unicode(os.urandom(8))
         self.socket.sendall(HANDSHAKE_STR.format(self.key).encode('ascii'))
         self.read_buf = deque()
         self.read_upgrade_response()
@@ -64,7 +64,7 @@ class WSClient(object):
         if rl != b'HTTP/1.1 101 Switching Protocols\r\n':
             raise ValueError('Server did not respond with correct switching protocols line')
         headers = read_headers(partial(next, lines))
-        key = as_base64_unicode(sha1(self.key + GUID_STR.encode('ascii')).digest())
+        key = as_base64_unicode(sha1((self.key + GUID_STR).encode('ascii')).digest())
         if headers.get('Sec-WebSocket-Accept') != key:
             raise ValueError('Server did not respond with correct key in Sec-WebSocket-Accept: {} != {}'.format(
                 key, headers.get('Sec-WebSocket-Accept')))
@@ -215,7 +215,7 @@ class WebSocketTest(BaseTest):
             for q in (b'', b'\xfe' * 125, b'\xfe' * 126, b'\xfe' * 127, b'\xfe' * 128, b'\xfe' * 65535, b'\xfe' * 65536):
                 simple_test([q], [q])
 
-            for payload in ['', 'ping', b'\x00\xff\xfe\xfd\xfc\xfb\x00\xff', b"\xfe" * 125]:
+            for payload in [b'', b'ping', b'\x00\xff\xfe\xfd\xfc\xfb\x00\xff', b"\xfe" * 125]:
                 simple_test([(PING, payload)], [(PONG, payload)])
 
             with server.silence_log:
@@ -260,7 +260,8 @@ class WebSocketTest(BaseTest):
                 isf_test(frags, close_code=INCONSISTENT_DATA, send_close=False)
 
                 frags, q = [], b'\xce\xba\xe1\xbd\xb9\xcf\x83\xce\xbc\xce\xb5\xed\xa0\x80\x80\x65\x64\x69\x74\x65\x64'
-                for i, b in enumerate(q):
+                for i in range(len(q)):
+                    b = q[i:i+1]
                     frags.append({'opcode':(TEXT if i == 0 else CONTINUATION), 'fin':1 if i == len(q)-1 else 0, 'payload':b})
                 isf_test(frags, close_code=INCONSISTENT_DATA, send_close=False, ignore_send_failures=True)
 
@@ -289,9 +290,10 @@ class WebSocketTest(BaseTest):
             simple_test([
                 {'opcode':TEXT, 'fin':0}, {'opcode':CONTINUATION, 'fin':0, 'payload':'x'}, {'opcode':CONTINUATION},], ['x'])
 
-            for q in (b'\xc2\xb5', b'\xce\xba\xe1\xbd\xb9\xcf\x83\xce\xbc\xce\xb5',  "Hello-µ@ßöäüàá-UTF-8!!".encode('utf-8')):
+            for q in (b'\xc2\xb5', b'\xce\xba\xe1\xbd\xb9\xcf\x83\xce\xbc\xce\xb5', "Hello-µ@ßöäüàá-UTF-8!!".encode('utf-8')):
                 frags = []
-                for i, b in enumerate(q):
+                for i in range(len(q)):
+                    b = q[i:i+1]
                     frags.append({'opcode':(TEXT if i == 0 else CONTINUATION), 'fin':1 if i == len(q)-1 else 0, 'payload':b})
                 simple_test(frags, [q.decode('utf-8')])