Work around wsgiref bug

This will allow tests to pass with most recent WebTest

setup.py

@@ -25,13 +25,7 @@
     + open('CHANGES.txt').read()
     )
 
-# pinning version, because of some incompatibility and test failures
-# see:
-# http://winbot.zope.org/builders/zope.testbrowser_py_265_32/builds/619/steps/test/logs/stdio
-WEBTEST = 'WebTest <= 1.3.4'
-
-tests_require = ['zope.testing',
-                 WEBTEST]
+tests_require = ['zope.testing']
 
 setup(
     name='zope.testbrowser',
@@ -65,6 +59,7 @@
         'zope.interface',
         'zope.schema',
         'pytz',
+        'WebTest',
         ],
     extras_require={
         'test': tests_require,
@@ -75,7 +70,7 @@
             'zope.app.testing >= 3.9.0dev',
             ],
         'wsgi': [
-            WEBTEST,
+                 # BBB
             ]
         },
     include_package_data=True,

src/zope/testbrowser/README.txt

@@ -28,7 +28,7 @@ There is also a special version of the ``Browser`` class which uses
 applications. It can be imported from ``zope.testbrowser.wsgi``:
 
     >>> from zope.testbrowser.wsgi import Browser
-    >>> from wsgiref.simple_server import demo_app
+    >>> from zope.testbrowser.testing import demo_app
     >>> browser = Browser('http://localhost/', wsgi_app=demo_app)
     >>> print browser.contents
     Hello world!

src/zope/testbrowser/testing.py

@@ -15,6 +15,7 @@
 """
 
 from zope.testbrowser.connection import Response as PublisherResponse
+from wsgiref.simple_server import demo_app as wsgiref_demo_app
 
 try:
     import zope.app.testing
@@ -29,3 +30,9 @@
                                               Browser)
 
 del have_zope_app_testing
+
+def demo_app(environ, start_response):
+    """PEP-3333 compatible demo app, that will never return unicode
+    """
+    refout = wsgiref_demo_app(environ, start_response)
+    return [s if isinstance(s, bytes) else s.encode('utf-8') for s in refout]

src/zope/testbrowser/tests/test_wsgi.py

@@ -14,11 +14,12 @@
 
 import unittest
 from urllib import urlencode
-from wsgiref.simple_server import demo_app
 
 import zope.testbrowser.wsgi
 from zope.testbrowser.ftests.wsgitestapp import WSGITestApplication
 
+from zope.testbrowser.testing import demo_app
+
 
 class SimpleLayer(zope.testbrowser.wsgi.Layer):