added Python 3.8 and removed 3.4 from circle build

.circleci/config.yml

@@ -7,23 +7,26 @@ jobs:
         - checkout
         - run: make
         - run: make ci
-    python34:
+    python35:
       docker:
-        - image: circleci/python:3.4
+        - image: circleci/python:3.5
       steps:
         - checkout
         - run: make
         - run: make ci
-    python35:
+    python37:
       docker:
-        - image: circleci/python:3.5
+        - image: circleci/python:3.7
       steps:
         - checkout
         - run: make
         - run: make ci
-    python37:
+    python38:
       docker:
-        - image: circleci/python:3.7
+        - image: circleci/python:3.8.0b2-buster
+          auth:
+            username: jmancuso9  # can specify string literal values
+            password: $DOCKERHUB_PASSWORD
       steps:
         - checkout
         - run: make
@@ -60,15 +63,15 @@ workflows:
           filters:  # required since `deploy` has tag filters AND requires `build`
             tags:
               only: /^v*/
-      - python34:
+      - python35:
           filters:  # required since `deploy` has tag filters AND requires `build`
             tags:
               only: /^v*/
-      - python35:
+      - python37:
           filters:  # required since `deploy` has tag filters AND requires `build`
             tags:
               only: /^v*/
-      - python37:
+      - python38:
           filters:  # required since `deploy` has tag filters AND requires `build`
             tags:
               only: /^v*/

tests/core/test_managers_mail_manager.py

@@ -70,7 +70,7 @@ def test_manager_sets_driver(self):
         MailManager(self.app).driver('mailtrap')
 
     def test_manager_sets_driver_throws_driver_not_found_exception(self):
-        with self.assertRaises(DriverNotFound, message="Should raise DriverNotFound error"):
+        with self.assertRaises(DriverNotFound):
             MailManager(self.app).driver('mailtrap')
 
     def test_drivers_are_resolvable_by_container(self):