Test mac on self-hosted runner

.github/workflows/mac.yml

@@ -0,0 +1,53 @@
+name: mac-ci
+
+on: [push, pull_request]
+
+jobs:
+
+  tests:
+    runs-on: [self-hosted, macOS]
+    if: github.repository == 'stfc/janus-core'
+    timeout-minutes: 30
+    strategy:
+      matrix:
+        python-version: ['3.9','3.10','3.11','3.12']
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v4
+        with:
+          version: "0.5.7"
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: uv sync --all-extras
+
+      - name: Run test suite
+        env:
+          # show timings of tests
+          PYTEST_ADDOPTS: "--durations=0"
+        run: uv run pytest --run-extra-mlips --cov janus_core --cov-append .
+
+      - name: Set Path
+        run: |
+          source ~/.zshrc
+          echo "PATH=$PATH" >> $GITHUB_ENV
+
+      - name: Report coverage to Coveralls
+        uses: coverallsapp/github-action@v2
+        with:
+          parallel: true
+          flag-name: run-${{ matrix.python-version }}
+          file: coverage.xml
+          base-path: janus_core
+
+  coverage:
+    needs: tests
+    runs-on: self-hosted
+    steps:
+      - name: Close parallel build
+        uses: coverallsapp/github-action@v2
+        with:
+          parallel-finished: true

docs/source/developer_guide/ci.rst

@@ -0,0 +1,29 @@
+======================
+Continuous Integration
+======================
+
+General instructions for setting up self-hosted GitHub runners can be found `here <https://docs.github.com/en/actions/hosting-your-own-runners>`_.
+
+This process typically involves:
+
+1. Add a new self-hosted runner on GitHub
+2. Run instructions from GitHub on your runner to download and configure
+3. Ensure tags added to the runner are unique, and match those in ``runs-on`` within the CI workflow
+
+
+MacOS self-hosted runner
+========================
+
+Currently, ``janus-core`` uses a self-hosted runner to run all unit tests on MacOS.
+
+To ensure the self-hosted runner remains active, we currently recommend using
+
+.. code-block:: bash
+
+    nohup ./run.sh &!
+
+This runs the script in the background, and disowns the process, allowing the ssh connection to be ended without killing the process.
+
+It would be preferable to `configure the runner application as a service <https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners/configuring-the-self-hosted-runner-application-as-a-service?platform=mac>`_,
+but currently this appears to lead to difficulties if the GUI is not active
+and/or ``sudo`` permissions are not used in running the service.

docs/source/developer_guide/index.rst

@@ -7,3 +7,4 @@ Developer guide
 
     get_started
     tutorial
+    ci