language: python
matrix:
  include:
    - python: 2.7
    - python: 3.3
    - python: 3.4
    - python: 3.5
    - python: 3.6
    - python: 3.7
      dist: xenial
      sudo: true
install:
- pip install coverage
- pip install coveralls
script:
 - cd test
 - env PYTHONPATH=.. python -m unittest --verbose all
 - cd ..
 - env PYTHONPATH=. coverage run test/all.py
after_success:
 - coveralls

language: python
matrix:
  include:
    - python: 2.7
    - python: 3.4
    - python: 3.5
    - python: 3.6
    - python: 3.7
    - python: 3.8
      dist: xenial
      sudo: true
install:
- pip install coverage
- pip install coveralls
script:
 - cd test
 - env PYTHONPATH=.. python -m unittest --verbose all
 - cd ..
 - env PYTHONPATH=. coverage run test/all.py
after_success:
 - coveralls

Remove CPython 3.3; add CPython 3.8
Remove CPython 3.3; add CPython 3.8

All still running on Xenial.  I should probably add Windows, macOS,
and think about a few Ubuntu versions one day?
