diff --git a/src/zope/testbrowser/tests/test_browser.py b/src/zope/testbrowser/tests/test_browser.py
index 049c16f..57d06f9 100644
--- a/src/zope/testbrowser/tests/test_browser.py
+++ b/src/zope/testbrowser/tests/test_browser.py
@@ -101,12 +101,12 @@ def test_relative_open_allowed_after_non_html_page(self):
     >>> browser = Browser(wsgi_app=app)
     >>> content_type = ('Content-Type', 'text/csv')
     >>> app.add_response(b'have,some,csv', headers=[content_type])
-    >>> content_type = ('Content-Type', 'text/html')
+    >>> content_type = ('Content-Type', 'text/html; charset=UTF-8')
     >>> app.add_response(b'have some html', headers=[content_type])
     >>> browser.open('https://localhost/foo/bar')
     >>> browser.open('/baz')
     >>> browser.contents
-    b'have some html'
+    'have some html'
     >>> browser.url
     'https://localhost/baz'
     """