ci: enhance tests workflow with proper coverage reporting

- Remove duplicate lint job from tests.yml (already exists in lint.yml)
- Add coverage reporting with pytest-cov and term-missing output
- Add codecov integration for coverage tracking
- Test matrix runs on Python 3.11 and 3.12
- All 14 unit tests now properly run in GitHub Actions
- Coverage XML report generated for external tools

Fixes missing unit tests in CI/CD pipeline

Author: dividor

.github/workflows/tests.yml

@@ -34,35 +34,14 @@ jobs:
         source .venv/bin/activate
         uv pip install -e ".[test]"
 
-    - name: Run tests
+    - name: Run tests with coverage
       run: |
         source .venv/bin/activate
-        python -m pytest
+        python -m pytest --cov=pia_mcp_server --cov-report=term-missing --cov-report=xml
 
-  lint:
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v4
-
-    - name: Set up Python
-      uses: actions/setup-python@v4
+    - name: Upload coverage to codecov
+      if: matrix.python-version == '3.11'
+      uses: codecov/codecov-action@v3
       with:
-        python-version: "3.11"
-
-    - name: Install uv
-      uses: astral-sh/setup-uv@v3
-      with:
-        version: "latest"
-
-    - name: Create virtual environment
-      run: uv venv
-
-    - name: Install dependencies
-      run: |
-        source .venv/bin/activate
-        uv pip install -e ".[dev]"
-
-    - name: Run Black
-      run: |
-        source .venv/bin/activate
-        black --check .
+        file: ./coverage.xml
+        fail_ci_if_error: false