Switch CI unit tests to py.test

  extends: [.python]

  needs: [Pin]

  script:

  - pip install -r requirements.txt -e . coverage[toml] nose

  - coverage run -m nose tests

  - pip install -r requirements.txt -e .

    coverage[toml]

    pytest

  - coverage run -m pytest tests

    --verbose

    --with-xunit --xunit-file=results/xunit.xml

    --junit-xml=results/xunit.xml

  after_script:

  - coverage report

  - coverage json