diff --git a/ckan/tests/controllers/test_home.py b/ckan/tests/controllers/test_home.py
index 038aa926f11..6b0287888fa 100644
--- a/ckan/tests/controllers/test_home.py
+++ b/ckan/tests/controllers/test_home.py
@@ -44,7 +44,7 @@ def test_email_address_nag(self):
         response = app.get(url=url_for('home.index'), extra_environ=env)
 
         assert 'update your profile' in response.body
-        assert url_for('user.edit') in response.body
+        assert str(url_for('user.edit')) in response.body
         assert ' and add your email address.' in response.body
 
     def test_email_address_no_nag(self):
diff --git a/ckan/tests/helpers.py b/ckan/tests/helpers.py
index 520b417d9dd..5586e000987 100644
--- a/ckan/tests/helpers.py
+++ b/ckan/tests/helpers.py
@@ -155,6 +155,10 @@ def flask_app(self):
             self._flask_app = self.app.apps['flask_app']._wsgi_app
         return self._flask_app
 
+    def post(self, url, *args, **kwargs):
+        url = url.encode('utf8')  # or maybe it should be url_encoded?
+        return super(CKANTestApp, self).post(url, *args, **kwargs)
+
 
 def _get_test_app():
     '''Return a webtest.TestApp for CKAN, with legacy templates disabled.
diff --git a/ckan/tests/legacy/functional/test_preview_interface.py b/ckan/tests/legacy/functional/test_preview_interface.py
index 73b9c628328..69f92a5f812 100644
--- a/ckan/tests/legacy/functional/test_preview_interface.py
+++ b/ckan/tests/legacy/functional/test_preview_interface.py
@@ -87,4 +87,4 @@ def test_iframe_is_shown(self):
 
     def test_iframe_url_is_correct(self):
         result = self.app.get(self.url)
-        assert self.preview_url in result.body, (self.preview_url, result.body)
+        assert str(self.preview_url) in result.body, (self.preview_url, result.body)
diff --git a/ckanext/datastore/tests/test_info.py b/ckanext/datastore/tests/test_info.py
index e351b7b38dd..7aee08e398a 100644
--- a/ckanext/datastore/tests/test_info.py
+++ b/ckanext/datastore/tests/test_info.py
@@ -73,4 +73,4 @@ def test_api_info(self):
             "http://test.ckan.net/api/3/action/datastore_search?resource_id=588dfa82-760c-45a2-b78a-e3bc314a4a9b&limit=5&q=title:jones",
         )
         for url in expected_urls:
-            assert url in page, url
+            assert str(url) in page, url
diff --git a/ckanext/multilingual/tests/test_multilingual_plugin.py b/ckanext/multilingual/tests/test_multilingual_plugin.py
index 8e5fbebd2c9..44dd082518b 100644
--- a/ckanext/multilingual/tests/test_multilingual_plugin.py
+++ b/ckanext/multilingual/tests/test_multilingual_plugin.py
@@ -71,8 +71,8 @@ def test_user_read_translation(self):
         # It is testsysadmin who created the dataset, so testsysadmin whom
         # we'd expect to see the datasets for.
         for user_name in ('testsysadmin',):
-            offset = h.url_for(
-                'user.read', id=user_name)
+            offset = str(h.url_for(
+                'user.read', id=user_name))
             for (lang_code, translations) in (
                     ('de', _create_test_data.german_translations),
                     ('fr', _create_test_data.french_translations),