tests workflow (Fatal1ty/mashumaro)

The tests workflow from Fatal1ty/mashumaro, explained and optimized by Latchkey.

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Source: Fatal1ty/mashumaro.github/workflows/main.ymlLicense Apache-2.0View source

What it does

This is the tests workflow from the Fatal1ty/mashumaro repository, a real project running GitHub Actions. It is shown here with attribution under its Apache-2.0 license.

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

The workflow

workflow (.yml)

name: tests

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

jobs:
  test-code-style:
    name: Code style tests
    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@v4
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v5
        with:
          python-version: ${{ matrix.python-version }}
          allow-prereleases: true
      - name: Install dependencies
        run: |
          python -m venv .venv
          source .venv/bin/activate
          pip install -r requirements-dev.txt
          pip install .
      - name: Run ruff
        run: |
          source .venv/bin/activate
          ruff check mashumaro
      - name: Run mypy
        run: |
          source .venv/bin/activate
          mypy mashumaro
      - name: Run black
        run: |
          source .venv/bin/activate
          black --check .
      - name: Run codespell
        run: |
          source .venv/bin/activate
          codespell mashumaro tests .github/*.md
          codespell README.md --ignore-words-list brunch

  test-posix:
    name: Tests on Posix
    needs:
      - test-code-style
    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@v4
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v5
      with:
        python-version: ${{ matrix.python-version }}
        allow-prereleases: true
    - name: Install dependencies
      run: |
        python -m venv .venv
        source .venv/bin/activate
        pip install -r requirements-dev.txt
        pip install .
    - name: Run tests with coverage
      run: |
        source .venv/bin/activate
        pytest --cov=mashumaro --cov=tests --cov-report=xml
    - name: Upload coverage reports to Codecov
      uses: codecov/codecov-action@v5
      with:
        token: ${{ secrets.CODECOV_TOKEN }}

  test-windows:
    name: Tests on Windows
    needs:
      - test-code-style
    runs-on: windows-latest
    strategy:
      fail-fast: false
      matrix:
        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
    steps:
    - uses: actions/checkout@v4
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v5
      with:
        python-version: ${{ matrix.python-version }}
        allow-prereleases: true
    - name: Install dependencies
      run: |
        python -m venv .venv
        .venv/Scripts/activate
        pip install -r requirements-dev.txt
        pip install .
        pip install tzdata
    - name: Run tests with coverage
      run: |
        .venv/Scripts/activate
        pytest --cov=mashumaro --cov=tests --cov-report=xml
    - name: Upload coverage reports to Codecov
      uses: codecov/codecov-action@v5
      with:
        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: tests
 
on:
  push:
    branches:
      - '*'
  pull_request:
    branches:
      - master
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  test-code-style:
    timeout-minutes: 30
    name: Code style tests
    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@v4
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v5
        with:
          cache: 'pip'
          python-version: ${{ matrix.python-version }}
          allow-prereleases: true
      - name: Install dependencies
        run: |
          python -m venv .venv
          source .venv/bin/activate
          pip install -r requirements-dev.txt
          pip install .
      - name: Run ruff
        run: |
          source .venv/bin/activate
          ruff check mashumaro
      - name: Run mypy
        run: |
          source .venv/bin/activate
          mypy mashumaro
      - name: Run black
        run: |
          source .venv/bin/activate
          black --check .
      - name: Run codespell
        run: |
          source .venv/bin/activate
          codespell mashumaro tests .github/*.md
          codespell README.md --ignore-words-list brunch
 
  test-posix:
    timeout-minutes: 30
    name: Tests on Posix
    needs:
      - test-code-style
    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@v4
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v5
      with:
        cache: 'pip'
        python-version: ${{ matrix.python-version }}
        allow-prereleases: true
    - name: Install dependencies
      run: |
        python -m venv .venv
        source .venv/bin/activate
        pip install -r requirements-dev.txt
        pip install .
    - name: Run tests with coverage
      run: |
        source .venv/bin/activate
        pytest --cov=mashumaro --cov=tests --cov-report=xml
    - name: Upload coverage reports to Codecov
      uses: codecov/codecov-action@v5
      with:
        token: ${{ secrets.CODECOV_TOKEN }}
 
  test-windows:
    timeout-minutes: 30
    name: Tests on Windows
    needs:
      - test-code-style
    runs-on: windows-latest
    strategy:
      fail-fast: false
      matrix:
        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
    steps:
    - uses: actions/checkout@v4
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v5
      with:
        cache: 'pip'
        python-version: ${{ matrix.python-version }}
        allow-prereleases: true
    - name: Install dependencies
      run: |
        python -m venv .venv
        .venv/Scripts/activate
        pip install -r requirements-dev.txt
        pip install .
        pip install tzdata
    - name: Run tests with coverage
      run: |
        .venv/Scripts/activate
        pytest --cov=mashumaro --cov=tests --cov-report=xml
    - name: Upload coverage reports to Codecov
      uses: codecov/codecov-action@v5
      with:
        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.
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.

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

This workflow runs 3 jobs (15 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

actions/checkout actions/setup-python codecov/codecov-action