Don't use tox in CircleCI

Author: Pithikos

.circleci/config.yml

@@ -9,14 +9,10 @@ jobs:
       - image: circleci/python:3
     steps:
       - checkout
-      - run:
-          name: install dependencies
-          command: |
-            sudo pip install tox
       - run:
           name: run tests
           command: |
-            tox -e py37
+            pytest
       - store_artifacts:
           path: test-reports
           destination: test-reports