tests workflow (sharsil/mailcat)

The tests workflow from sharsil/mailcat, explained and optimized by Latchkey.

What it does

This is the tests workflow from the sharsil/mailcat 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

name: tests

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  unit:
    name: unit tests (py${{ matrix.python-version }})
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        python-version: ["3.10", "3.11", "3.12", "3.13"]
    steps:
      - uses: actions/checkout@v4

      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v5
        with:
          python-version: ${{ matrix.python-version }}
          cache: pip

      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          pip install .
          pip install pytest==9.0.3 pytest-asyncio==1.3.0

      - name: Run unit tests (network-free)
        run: python -m pytest tests/test_mailcat.py -v

The same workflow, on Latchkey

Removes redundant runs and caps runaway jobs. Added and changed lines are highlighted.

name: tests
 
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  unit:
    timeout-minutes: 30
    name: unit tests (py${{ matrix.python-version }})
    runs-on: latchkey-small
    strategy:
      fail-fast: false
      matrix:
        python-version: ["3.10", "3.11", "3.12", "3.13"]
    steps:
      - uses: actions/checkout@v4
 
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v5
        with:
          python-version: ${{ matrix.python-version }}
          cache: pip
 
      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          pip install .
          pip install pytest==9.0.3 pytest-asyncio==1.3.0
 
      - name: Run unit tests (network-free)
        run: python -m pytest tests/test_mailcat.py -v
 

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• Cancel superseded runs when a branch or PR gets a newer push.
• 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 (4 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