The virtual env cannot be sourced so easily

.gitlab-ci.yml

 test python 3:
   script:
     - virtualenv --python=python3 env
-    - source env/bin/activate
-    - python setup.py develop
-    - python manage.py test
+    - env/bin/python setup.py develop
+    - env/bin/python manage.py test
   stage: test
   tags:
     - test