test workflow (wemake-services/wemake-python-styleguide)

The test workflow from wemake-services/wemake-python-styleguide, explained and optimized by Latchkey.

What it does

This is the test workflow from the wemake-services/wemake-python-styleguide 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

'on':
  push:
    branches:
      - master
  pull_request:
  workflow_dispatch:

concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
  cancel-in-progress: true

permissions:
  contents: read

jobs:
  build:
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        python-version: ['3.10', '3.11', '3.12', '3.13', '3.14']
    steps:
      - uses: actions/checkout@v7.0.0
        with:
          persist-credentials: false
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v6.3.0
        with:
          python-version: ${{ matrix.python-version }}
      - name: Install poetry
        run: |
          curl -sSL 'https://install.python-poetry.org' | python

          # Adding `poetry` to `$PATH`:
          echo "$HOME/.poetry/bin" >> "$GITHUB_PATH"
      - name: Install dependencies
        run: |
          poetry config virtualenvs.in-project true
          poetry run pip install -U pip
          poetry install
      - name: Run tests
        run: make test
      - name: Upload coverage to Codecov
        uses: codecov/codecov-action@v7.0.0
        with:
          files: ./coverage.xml
          token: ${{ secrets.CODECOV_TOKEN }}

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
 
'on':
  push:
    branches:
      - master
  pull_request:
  workflow_dispatch:
 
concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
  cancel-in-progress: true
 
permissions:
  contents: read
 
jobs:
  build:
    timeout-minutes: 30
    runs-on: latchkey-small
    strategy:
      fail-fast: false
      matrix:
        python-version: ['3.10', '3.11', '3.12', '3.13', '3.14']
    steps:
      - uses: actions/checkout@v7.0.0
        with:
          persist-credentials: false
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v6.3.0
        with:
          cache: 'pip'
          python-version: ${{ matrix.python-version }}
      - name: Install poetry
        run: |
          curl -sSL 'https://install.python-poetry.org' | python
 
          # Adding `poetry` to `$PATH`:
          echo "$HOME/.poetry/bin" >> "$GITHUB_PATH"
      - name: Install dependencies
        run: |
          poetry config virtualenvs.in-project true
          poetry run pip install -U pip
          poetry install
      - name: Run tests
        run: make test
      - name: Upload coverage to Codecov
        uses: codecov/codecov-action@v7.0.0
        with:
          files: ./coverage.xml
          token: ${{ secrets.CODECOV_TOKEN }}
 

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.
• 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.

1 third-party action is referenced by a movable tag. Pin it to the commit SHA (Latchkey resolves and applies this automatically) so a repointed tag cannot change what runs.

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
• Network fetches

This workflow runs 1 job (5 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