cleanup and a lot more tests

.travis.yml

@@ -1,11 +1,10 @@
 language: python
 python:
-  - "3.6"
   - "3.7"
   - "3.8"
 # command to install dependencies
-install: "pip install nose coverage python-coveralls"
+install: "pip install pytest pytest-black pytest-cov pytest-mypy pytest-pylint pytest-flake8 coveralls"
 # command to run tests
-script: nosetests -v --with-coverage --cover-package=pyrad
+script: pytest --black --pylint --pylint-jobs=4 --mypy --cov=pyrad3 --flake8
 after_success:
   - coveralls