.travis.yml

os: linux
arch: x64
language: python
env: PYTHON=python   # 'python' points to Python 2.7 on macOS but points to Python 3.8 on Linux and Windows; 'python3' is a 'command not found' error on Windows
install: # NB: you can't have a colon anywhere in the line (hence '%c' % 58)
    - $PYTHON -c 'import sys,struct,platform;print("{\n%s}"%"".join("    %25r %c %r,\n"%(c,58,eval(c)) for c in """struct.calcsize("P")*8 sys.maxsize platform.machine() platform.architecture()""".split()))'
    - $PYTHON -m pip install --upgrade pip
    - $PYTHON -m pip install pytest
    - $PYTHON -m pip install .
    #- $PYTHON -m pip install -r requirements.txt

script:
    - $PYTHON -m pytest -v .

matrix:
    include:
        #- python: "2.6"  # update 20200807: Travis no longer supports this
        - python: "2.7"
        #- python: "3.2" # pytest does not support this version; update 20200807: Travis no longer supports this either
        #- python: "3.3" # pytest does not support this version; update 20200807: Travis no longer supports this either
        - python: "3.4"
        - python: "3.5"
        - python: "3.6"
        - python: "3.7"
        - python: "3.8"
        - python: "3.9-dev" # no full release of 3.9 available on Travis as at 20200807
          
        #- name: "Python 3.8 on 32-bit Linux"
        #  arch: x86     # weirdly, the architecture is reported as i386 in the Travis matrix, but sys.maxsize is still 9223372036854775807, platform.machine() is still 'x86_64' and platform.architecture() is still ('64bit', 'ELF')
        #  python: 3.8
          
        - name: "Python 2.x on macOS"
          os: osx   # seems to come with python and python3 but it's less clear how to take control of precise version---maybe via `brew install pyenv-virtualenv` (which takes a loooong time) plus (unknown) extra steps
          language: generic
          env: PYTHON=python2
          
        - name: "Python 3.x on macOS"
          os: osx
          language: generic
          env: PYTHON=python3

        #- name: "Python 2.7 on Windows"
        #  os: windows
        #  language: shell
        #  env:
        #      - PYTHON=python
        #      - PATH=/c/Python27:/c/Python27/Scripts:$PATH      # note that the path must change according to the Python version
        #  before_install:
        #      - choco install python --version=2.7.11  # 2.7.11 appears to be the last 2.x version chocolatey offers, and you can't get away with saying just 2.7
        #      - $PYTHON -m ensurepip # Python 2.7 for Windows seems to ship without pip
        #      # Unfortunately ensurepip fails with an AttributeError deep inside pip-1.5.6-py2.py3-none-any.whl/pip/_vendor/distlib/scripts.py
        #      # So that's a deal-breaker, unless we somehow work around the complete absence of pip

        - name: "Python 3.8 on Windows"
          os: windows
          language: shell
          env:
              - PYTHON=python
              - PATH=/c/Python38:/c/Python38/Scripts:$PATH      # note that the path must change according to the Python version
          before_install:
              - choco install python --version=3.8

        #- name: "Python 3.8 on 32-bit Windows"
        #  os: windows
        #  arch: x86  # This appears to have no effect. The architecture is still reported as AMD64 in the Travis matrix, and the printed values all show that 64-bit Python is running
        #  language: shell
        #  env:
        #      - PYTHON=python
        #      - PATH=/c/Python38:/c/Python38/Scripts:$PATH      # note that the path must change according to the Python version
        #  before_install:
        #      - choco install python --version=3.8