tox-gh

tox-gh is a tox plugin, which helps run tox on GitHub Actions with multiple different Python versions on multiple workers in parallel.

Features

When running tox on GitHub Actions, tox-gh:

• detects which environment to run based on configurations (or bypasses detection and sets it explicitly via the TOX_GH_MAJOR_MINOR environment variable),
• provides utilities such as grouping log lines.

Usage

1. Add configurations under [gh] section along with your tox configuration.
2. Install tox-gh package in the GitHub Actions workflow before running tox command.

Examples

Basic Example

Add [gh] section to the same file as tox configuration.

If you're using tox.ini:

[gh]
python =
    3.14t = 3.14t
    3.14 = 3.14, type, dev, pkg_meta
    3.13 = 3.13
    3.12 = 3.12

For tox.toml:

[gh.python]
"3.14t" = ["3.14t"]
"3.14" = ["3.14", "type", "pkg_meta"]
"3.13" = ["3.13"]
"3.12" = ["3.12"]

For pyproject.toml:

[tool.tox.gh.python]
"3.14t" = ["3.14t"]
"3.14" = ["3.14", "type", "pkg_meta"]
"3.13" = ["3.13"]
"3.12" = ["3.12"]

This will run a different set of tox environments on different Python versions set up via GitHub setup-python action:

• on Python 3.14t job, tox runs 3.14t environment,
• on Python 3.14 job, tox runs 3.14, type and pkg_meta environments,
• on Python 3.13 job, tox runs 3.13 environment,
• on Python 3.12 job, tox runs 3.12 environment,

Workflow Configuration

A bare-bones example would be .github/workflows/check.yaml:

jobs:
  test:
    name: test with ${{ matrix.env }} on ${{ matrix.os }}
    runs-on: ${{ matrix.os }}
    strategy:
      fail-fast: false
      matrix:
        env:
          - "3.14t"
          - "3.14"
          - "3.13"
        os:
          - ubuntu-latest
          - macos-latest
    steps:
      - uses: actions/checkout@v5
      - name: Install the latest version of uv
        uses: astral-sh/setup-uv@v7
      - name: Install tox
        run: uv tool install --python-preference only-managed --python 3.14 tox --with tox-uv --with tox-gh
      - name: Install Python
        if: matrix.env != '3.14'
        run: uv python install --python-preference only-managed ${{ matrix.env }}
      - name: Setup test suite
        run: tox run -vv --notest --skip-missing-interpreters false
        env:
          TOX_GH_MAJOR_MINOR: ${{ matrix.env }}
      - name: Run test suite
        run: tox run --skip-pkg-install
        env:
          TOX_GH_MAJOR_MINOR: ${{ matrix.env }}

A more exhaustive example would be .github/workflows/check.yaml:

name: check
on:
  workflow_dispatch:
  push:
    branches: ["main"]
    tags-ignore: ["**"]
  pull_request:
  schedule: # Runs at 8 AM every day
    - cron: "0 8 * * *"

concurrency:
  group: check-${{ github.ref }}
  cancel-in-progress: true

jobs:
  test:
    name: test with ${{ matrix.env }} on ${{ matrix.os }}
    runs-on: ${{ matrix.os }}
    strategy:
      fail-fast: false
      matrix:
        env:
          - "3.14t"
          - "3.14"
          - "3.13"
        os:
          - ubuntu-latest
          - macos-latest
          - windows-latest
    steps:
      - uses: actions/checkout@v5
        with:
          fetch-depth: 0
      - name: Install the latest version of uv
        uses: astral-sh/setup-uv@v7
        with:
          enable-cache: true
          cache-dependency-glob: "pyproject.toml"
          github-token: ${{ secrets.GITHUB_TOKEN }}
      - name: Add .local/bin to Windows PATH
        if: runner.os == 'Windows'
        shell: bash
        run: echo "$USERPROFILE/.local/bin" >> $GITHUB_PATH
      - name: Install tox
        run: uv tool install --python-preference only-managed --python 3.14 tox --with tox-uv --with tox-gh
      - name: Install Python
        if: matrix.env != '3.14'
        run: uv python install --python-preference only-managed ${{ matrix.env }}
      - name: Setup test suite
        run: tox run -vv --notest --skip-missing-interpreters false
        env:
          TOX_GH_MAJOR_MINOR: ${{ matrix.env }}
      - name: Run test suite
        run: tox run --skip-pkg-install
        env:
          TOX_GH_MAJOR_MINOR: ${{ matrix.env }}

FAQ

• When a list of environments to run is specified explicitly via -e option or TOXENV environment variable tox-gh respects the given environments and simply runs the given environments without enforcing its configuration.
• The plugin only activates if the environment variable GITHUB_ACTIONS is true.