Add unit tests documentation

docs/source/contributing/testing.md

@@ -4,3 +4,49 @@ Tests are of three different kinds:
 - Unit tests
 - Provider focused integration tests
 - Client SDK tests
+
+## Unit Tests
+
+Unit tests verify individual components and functions in isolation. They are fast, reliable, and don't require external services.
+
+### Prerequisites
+
+1. **Python Environment**: Ensure you have Python 3.12+ installed
+2. **uv Package Manager**: Install `uv` if not already installed
+3. **Virtual Environment**: Activate the project's virtual environment
+
+### Running Unit Tests
+
+#### Using the Unit Test Script (Recommended)
+
+The easiest way to run unit tests is using the provided script:
+
+```bash
+# Activate virtual environment
+uv venv .venv --python 3.12
+source .venv/bin/activate
+
+# Install dependencies
+uv pip install -r requirements.txt
+
+# Run all unit tests and generate coverage report
+PYTHON_VERSION=3.12 ./scripts/unit-tests.sh
+```
+
+### Test Configuration
+
+- **Test Discovery**: Tests are automatically discovered in the `tests/unit/` directory
+- **Async Support**: Tests use `--asyncio-mode=auto` for automatic async test handling
+- **Coverage**: Tests generate coverage reports in `htmlcov/` directory
+- **Python Version**: Defaults to Python 3.12, but can be overridden with `PYTHON_VERSION` environment variable
+
+### Coverage Reports
+
+After running tests, you can view coverage reports:
+
+```bash
+# Open HTML coverage report in browser
+open htmlcov/index.html  # macOS
+xdg-open htmlcov/index.html  # Linux
+start htmlcov/index.html  # Windows
+```