docs: update README and add test infrastructure

- Enhance .gitignore with comprehensive Python patterns
- Improve README with better setup and testing instructions
- Add test infrastructure:
  * Test requirements file
  * Environment setup script
  * Test runner script
  * Comprehensive test suite
  * Coverage configuration

README.md

@@ -44,20 +44,26 @@ You can try out a live demo at [https://demo-oidc.cl1.parano.ch/](https://demo-o
    cd oidc-validator
    ```
 
-2. Install dependencies:
+2. Set up virtual environment and install dependencies:
 
    ```bash
-   pip install -r requirements.txt
+   ./setup_test_env.sh
    ```
 
-3. Set environment variables:
+3. Activate the virtual environment:
+
+   ```bash
+   source venv/bin/activate
+   ```
+
+4. Set environment variables:
 
    ```bash
    export CLIENT_ID=your_oidc_client_id
    export CLIENT_SECRET=your_oidc_client_secret  # Required for token refresh
    ```
 
-4. Run the application:
+5. Run the application:
 
    ```bash
    uvicorn main:app --host 0.0.0.0 --port 8000 --reload
@@ -118,17 +124,30 @@ The application can be configured using the following environment variables:
 
 ### Running Tests
 
-Currently, there are no automated tests. You can manually test the endpoints using curl:
+This project includes a comprehensive test suite. To run the tests:
 
-```bash
-# Health check
-curl http://localhost:8000/health
+1. Set up the virtual environment:
+   ```bash
+   ./setup_test_env.sh
+   ```
 
-# Token validation (requires valid JWT token)
-curl -X POST http://localhost:8000/validate-token \
-  -H "Content-Type: application/json" \
-  -d '{"id_token": "your.jwt.token.here"}'
-```
+2. Run the tests:
+
+   ```bash
+   ./run_tests.sh
+   ```
+
+This will run all tests with coverage reporting and generate an HTML coverage report in the `htmlcov/` directory.
+
+The test suite covers:
+
+- API endpoint testing
+- Token validation logic
+- Error handling
+- Utility functions
+- Edge cases
+
+For more detailed information about testing, see [tests/README.md](tests/README.md).
 
 ### Deployment Notes