ci(backend-testing-01): add GitHub Actions workflow for tests

- Triggers on push to main/feature branches and PRs
- Runs unit tests with CI=true (skips hardware tests)
- Generates coverage report with pytest-cov
- Uploads coverage to Codecov
- Includes Ruff linting job (continue-on-error)
- Uses Python 3.11 with pip caching

.github/workflows/test.yml

@@ -0,0 +1,80 @@
+name: Tests
+
+on:
+  push:
+    branches: [ "main", "feature/*" ]
+    paths:
+      - '**.py'
+      - 'requirements*.txt'
+      - 'pyproject.toml'
+      - 'tests/**'
+      - '.github/workflows/test.yml'
+  pull_request:
+    branches: [ "main" ]
+    paths:
+      - '**.py'
+      - 'requirements*.txt'
+      - 'pyproject.toml'
+      - 'tests/**'
+      - '.github/workflows/test.yml'
+  # Allow manual trigger
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Python 3.11
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+          cache: 'pip'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+          pip install -r requirements-dev.txt
+
+      - name: Run unit tests with coverage
+        env:
+          CI: true
+        run: |
+          pytest tests/unit/ -v --cov=modules --cov=main --cov-report=xml --cov-report=term-missing
+
+      - name: Upload coverage reports to Codecov
+        uses: codecov/codecov-action@v4
+        if: always()
+        with:
+          file: ./coverage.xml
+          fail_ci_if_error: false
+          verbose: true
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+
+  lint:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Python 3.11
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+          cache: 'pip'
+
+      - name: Install linting dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install ruff
+
+      - name: Run Ruff linter
+        run: |
+          ruff check --output-format=github .
+        continue-on-error: true