Run tests for multiple language versions in GitHub actions in a Docker container

Question

I’m trying to setup GitHub actions for a Python package. I believe the most sane way to do so is what I’m used to from GitLab; run a set of commands inside of a docker image. I would like to use a matrix to test multiple Python versions.

So far I have defined the following workflow:

name: Pytest

on:
  - push
  - pull_request

jobs:
  pytest:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version:
          - 3.5
          - 3.6
          - 3.7
          - 3.8
    container: python:${{ python-version }}-alpine
    steps:
      - uses: actions/checkout@v2
      - name: Install
        run: |
          pip install poetry
          poetry install
      - name: PyTest
        run: poetry run pytest

The result can be seen here: https://github.com/remcohaszing/pywakeonlan/actions/runs/87630190

This shows the following error:

The workflow is not valid. .github/workflows/pytest.yaml (Line: 17, Col: 16): Unrecognized named-value: 'python-version'. Located at position 1 within expression: python-version

How do I fix this workflow?

DannyB DannyB · Accepted Answer · 2020-04-25T16:12:35

A couple of points to try:

1) To use values from the matrix, you need to use ${{ matrix.python-version }}. For more information, see the documentation for jobs.<job_id>.strategy.matrix.

2) You do not necessarily need to use containers to test multiple versions. GitHub Actions supports this out of the box using language specific "setup" actions. For example, see the official setup-python action. Here is an example of how they do it:

jobs:
  build:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version: [ '2.x', '3.x', 'pypy2', 'pypy3' ]
    name: Python ${{ matrix.python-version }} sample
    steps:
      - uses: actions/checkout@v2
      - name: Setup python
        uses: actions/setup-python@v1
        with:
          python-version: ${{ matrix.python-version }}
          architecture: x64
      - run: python my_script.py

Run tests for multiple language versions in GitHub actions in a Docker container

1 Answers