diff --git a/ecommerce/extensions/analytics/tests/test_middleware.py b/ecommerce/extensions/analytics/tests/test_middleware.py
index 64adfd5ac3d..b37526b63c1 100644
--- a/ecommerce/extensions/analytics/tests/test_middleware.py
+++ b/ecommerce/extensions/analytics/tests/test_middleware.py
@@ -19,7 +19,7 @@ class TrackingMiddlewareTests(TestCase):
 
     def setUp(self):
         super(TrackingMiddlewareTests, self).setUp()
-        self.middleware = middleware.TrackingMiddleware()
+        self.middleware = middleware.TrackingMiddleware(get_response=lambda request: None)
         self.request_factory = RequestFactory()
         self.user = self.create_user()
 
diff --git a/ecommerce/extensions/catalogue/models.py b/ecommerce/extensions/catalogue/models.py
index 98049598ed7..117d7e246e7 100644
--- a/ecommerce/extensions/catalogue/models.py
+++ b/ecommerce/extensions/catalogue/models.py
@@ -97,8 +97,8 @@ def is_executive_education_2u_product(self):
             CertificateType.UNPAID_EXECUTIVE_EDUCATION
         ]
 
-    def save(self, *args, **kwargs):
-        super(Product, self).save(*args, **kwargs)  # pylint: disable=bad-super-call
+    def clean(self):
+        super().clean()
         try:
             if not isinstance(self.attr.note, str) and self.attr.note is not None:
                 log_message_and_raise_validation_error(
diff --git a/ecommerce/extensions/partner/apps.py b/ecommerce/extensions/partner/apps.py
index 8d7820235c1..4d867c3f459 100644
--- a/ecommerce/extensions/partner/apps.py
+++ b/ecommerce/extensions/partner/apps.py
@@ -1,7 +1,7 @@
 
 
-from oscar.apps.partner.apps import PartnerConfig as CorePartnerConfig
+from oscar.apps.partner import apps
 
 
-class PartnerConfig(CorePartnerConfig):
+class PartnerConfig(apps.PartnerConfig):
     name = 'ecommerce.extensions.partner'
diff --git a/ecommerce/extensions/payment/core/tests/test_sdn.py b/ecommerce/extensions/payment/core/tests/test_sdn.py
index 2597a5b9203..00497a261bb 100644
--- a/ecommerce/extensions/payment/core/tests/test_sdn.py
+++ b/ecommerce/extensions/payment/core/tests/test_sdn.py
@@ -479,7 +479,7 @@ def test_sdn_is_down_sdn_fallback_called(
         If there is no hit, allow purchase.
         """
         request = RequestFactory().post('/payment/cybersource/submit/')
-        middleware = SessionMiddleware()
+        middleware = SessionMiddleware(get_response=lambda request: None)
         middleware.process_request(request)
         request.session.save()
         site_configuration = self.site.siteconfiguration