Test Python package workflow (avast/pytest-docker)

The Test Python package workflow from avast/pytest-docker, explained and optimized by Latchkey.

What it does

This is the Test Python package workflow from the avast/pytest-docker repository, a real project running GitHub Actions. It is shown here with attribution under its MIT license.

Below, Latchkey shows a faster, safer version produced by its optimization engine.

The workflow

---
name: Test Python package
on: [pull_request, push]

jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
        pytest-version: [4, 5, 6, 7, 8, 9]
        exclude:
          - python-version: "3.8"
            pytest-version: 9
          - python-version: "3.9"
            pytest-version: 9
    steps:
      - uses: actions/checkout@v2
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v2
        with:
          python-version: ${{ matrix.python-version }}
      - name: Install dependencies, pytest ${{ matrix.pytest-version }}
        run: |
          python -m pip install --upgrade pip setuptools
          pip install pytest==${{ matrix.pytest-version }}
          pip install ".[tests]"
      - name: Build image
        run: |
          docker compose -f tests/docker-compose.yml pull
          docker compose -f tests/docker-compose.yml build
      - name: Run tests
        run: |
          pytest -c setup.cfg
      - name: Stop Docker compose
        run: |
          docker compose -f tests/docker-compose.yml down

The same workflow, on Latchkey

Estimated ~20% faster on cache hits, plus fewer wasted runs and a safer supply chain. Added and changed lines are highlighted.

---
name: Test Python package
on: [pull_request, push]
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  test:
    timeout-minutes: 30
    runs-on: latchkey-small
    strategy:
      matrix:
        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
        pytest-version: [4, 5, 6, 7, 8, 9]
        exclude:
          - python-version: "3.8"
            pytest-version: 9
          - python-version: "3.9"
            pytest-version: 9
    steps:
      - uses: actions/checkout@v2
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v2
        with:
          cache: 'pip'
          python-version: ${{ matrix.python-version }}
      - name: Install dependencies, pytest ${{ matrix.pytest-version }}
        run: |
          python -m pip install --upgrade pip setuptools
          pip install pytest==${{ matrix.pytest-version }}
          pip install ".[tests]"
      - name: Build image
        run: |
          docker compose -f tests/docker-compose.yml pull
          docker compose -f tests/docker-compose.yml build
      - name: Run tests
        run: |
          pytest -c setup.cfg
      - name: Stop Docker compose
        run: |
          docker compose -f tests/docker-compose.yml down
 

What changed

• Run on Latchkey managed runners with one line (runs-on), which apply the fixes below automatically and self-heal transient failures. This example uses latchkey-small; pick the runner size that fits the job.
• Cancel superseded runs when a branch or PR gets a newer push.
• Cache dependency installs on the setup step so they are served from cache.
• Add a job timeout so a hung step cannot burn hours of runner time.

What Latchkey heals here

This workflow has steps that commonly fail on transient issues (network, registries, flaky browsers). On Latchkey managed runners they are detected, retried, and self-healed instead of failing your build:

• Dependency installs

This workflow runs 1 job (36 with the matrix expanded) per trigger. On Latchkey the same minutes cost up to 58% less than GitHub-hosted, with zero queue time.

Actions used in this workflow