diff --git a/src/zope/server/http/tests/test_wsgiserver.py b/src/zope/server/http/tests/test_wsgiserver.py
index 7b32c9a..b4381e9 100644
--- a/src/zope/server/http/tests/test_wsgiserver.py
+++ b/src/zope/server/http/tests/test_wsgiserver.py
@@ -54,8 +54,8 @@ class Conflict(Exception):
     Pseudo ZODB conflict error.
     """
 
-ERROR_RESPONSE = "error occurred"
-RESPONSE = "normal response"
+ERROR_RESPONSE = b"error occurred"
+RESPONSE = b"normal response"
 
 class DummyException(Exception):
     value = "Dummy Exception to test start_response"
@@ -181,7 +181,7 @@ def application(environ, start_response):
 
         self.port = self.server.socket.getsockname()[1]
         self.run_loop = 1
-        self.thread = Thread(target=self.loop)
+        self.thread = Thread(target=self.loop, name='test_wsgiserver')
         self.thread.start()
         sleep(0.1)  # Give the thread some time to start.
 
@@ -196,7 +196,7 @@ def loop(self):
         while self.run_loop:
             poll(0.1, socket_map)
 
-    def invokeRequest(self, path='/', add_headers=None, request_body='',
+    def invokeRequest(self, path='/', add_headers=None, request_body=b'',
                       return_response=False):
         h = HTTPConnection(LOCALHOST, self.port)
         h.putrequest('GET', path)
@@ -216,7 +216,7 @@ def invokeRequest(self, path='/', add_headers=None, request_body='',
         if length:
             response_body = response.read(length)
         else:
-            response_body = ''
+            response_body = b''
 
         self.assertEqual(length, len(response_body))
 
@@ -228,7 +228,7 @@ def testDeeperPath(self):
         self.assertEqual(status, 200)
         expect_response = 'URL invoked: http://%s:%d/folder/item' % (
             LOCALHOST, self.port)
-        self.assertEqual(response_body, expect_response)
+        self.assertEqual(response_body, expect_response.encode())
 
     def testNotFound(self):
         status, response_body = self.invokeRequest('/foo/bar')
@@ -271,12 +271,12 @@ def testServerAsProxy(self):
         self.assertEqual(
             response.getheader('Via'), 'zope.server.http (Browser)')
         # And the content got here too.
-        self.assertEqual(response.read(), 'Proxied Content')
+        self.assertEqual(response.read(), b'Proxied Content')
 
     def testWSGIVariables(self):
         # Assert that the environment contains all required WSGI variables
         status, response_body = self.invokeRequest('/wsgi')
-        wsgi_variables = set(response_body.split())
+        wsgi_variables = set(response_body.decode().split())
         self.assertEqual(wsgi_variables,
                          set(['wsgi.version', 'wsgi.url_scheme', 'wsgi.input',
                               'wsgi.errors', 'wsgi.multithread',
@@ -284,31 +284,31 @@ def testWSGIVariables(self):
 
     def testWSGIVersion(self):
         status, response_body = self.invokeRequest('/wsgi/version')
-        self.assertEqual("(1, 0)", response_body)
+        self.assertEqual(b"(1, 0)", response_body)
 
     def testWSGIURLScheme(self):
         status, response_body = self.invokeRequest('/wsgi/url_scheme')
-        self.assertEqual('http', response_body)
+        self.assertEqual(b'http', response_body)
 
     def testWSGIMultithread(self):
         status, response_body = self.invokeRequest('/wsgi/multithread')
-        self.assertEqual('True', response_body)
+        self.assertEqual(b'True', response_body)
 
     def testWSGIMultiprocess(self):
         status, response_body = self.invokeRequest('/wsgi/multiprocess')
-        self.assertEqual('True', response_body)
+        self.assertEqual(b'True', response_body)
 
     def testWSGIRunOnce(self):
         status, response_body = self.invokeRequest('/wsgi/run_once')
-        self.assertEqual('False', response_body)
+        self.assertEqual(b'False', response_body)
 
     def testWSGIProxy(self):
         status, response_body = self.invokeRequest(
             'https://zope.org:8080/wsgi/proxy_scheme')
-        self.assertEqual('https', response_body)
+        self.assertEqual(b'https', response_body)
         status, response_body = self.invokeRequest(
             'https://zope.org:8080/wsgi/proxy_host')
-        self.assertEqual('zope.org:8080', response_body)
+        self.assertEqual(b'zope.org:8080', response_body)
 
     def test_ensure_multiple_task_write_calls(self):
         # In order to get data out as fast as possible, the WSGI server needs
@@ -316,7 +316,7 @@ def test_ensure_multiple_task_write_calls(self):
         orig_app = self.server.application
         def app(eviron, start_response):
             start_response('200 Ok', [])
-            return ['This', 'is', 'my', 'response.']
+            return [b'This', b'is', b'my', b'response.']
         self.server.application = app
 
         class FakeTask:
@@ -444,13 +444,14 @@ def __init__(self, value):
             def __iter__(self):
                 return self
 
-            def next(self):
-                return self._iter.next()
+            def __next__(self):
+                return next(self._iter)
+            next = __next__
 
             def close(self):
                 self.closed = True
 
-        iterator = CloseableIterator(["Klaatu", "barada", "nikto"])
+        iterator = CloseableIterator([b"Klaatu", b"barada", b"nikto"])
         def app(environ, start_response):
             start_response("200 Ok", [], None)
             return iterator
@@ -484,7 +485,7 @@ def _getServerClass(self):
     def testWSGIVariables(self):
         # Assert that the environment contains all required WSGI variables
         status, response_body = self.invokeRequest('/wsgi')
-        wsgi_variables = set(response_body.split())
+        wsgi_variables = set(response_body.decode().split())
         self.assertEqual(wsgi_variables,
                          set(['wsgi.version', 'wsgi.url_scheme', 'wsgi.input',
                               'wsgi.errors', 'wsgi.multithread',