Fix: add example to tests ci page

ci-tests-data/tests-ci.md

@@ -17,4 +17,70 @@ It allows users to contribute code, documentation fixes and more without
 having to create development environments, run tests and build documentation
 locally.
 
-## TODO: add section with GitHub CI examples here
+## Example GitHub action that runs tests
+
+Below is an example github action that runs tests using nox
+across both Windows, Mac and Linux and on Python versions
+3.9-3.11. It also includes two steps that make your build more
+efficient so your dependencies aren't downloaded multiple times.
+
+```yaml
+name: Pytest unit/integration
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+
+# Use bash by default in all jobs
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  build-test:
+    name: Test Run (${{ matrix.python-version }}, ${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: ["ubuntu-latest", "macos-latest", "windows-latest"]
+        python-version: ["3.9", "3.10", "3.11"]
+
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          # fetch more than the last single commit to help scm generate proper version
+          fetch-depth: 20
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      # This step and the step below are an optional steps to cache variables to make your build faster / more efficient
+      - name: Set Variables
+        id: set_variables
+        shell: bash
+        run: |
+          echo "PY=$(python -c 'import hashlib, sys;print(hashlib.sha256(sys.version.encode()+sys.executable.encode()).hexdigest())')" >> $GITHUB_OUTPUT
+          echo "PIP_CACHE=$(pip cache dir)" >> $GITHUB_OUTPUT
+      - name: Cache dependencies
+        uses: actions/cache@v3
+        with:
+          path: ${{ steps.set_variables.outputs.PIP_CACHE }}
+          key: ${{ runner.os }}-pip-${{ steps.set_variables.outputs.PY }}
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install nox
+      - name: List installed packages
+        run: pip list
+      - name: Run tests with pytest & nox
+        run: |
+          nox -s tests-${{ matrix.python-version }}
+      # You only need to upload code coverage once to codecov
+      - name: Upload coverage to Codecov
+        if: ${{ matrix.os == 'ubuntu-latest' &&  matrix.python-version == '3.10'}}
+        uses: codecov/codecov-action@v3
+```