Initial commit: scheduler service extraction from portainer-core

Extracted standalone scheduler service with:
- FastAPI REST API for task management
- APScheduler-based task execution
- PostgreSQL persistence
- Docker container support
- Gitea Actions CI/CD workflow

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/README.md

@@ -0,0 +1,202 @@
+# Scheduler Tests
+
+Comprehensive test suite for The Scheduler using pytest.
+
+## Test Structure
+
+```
+tests/
+├── conftest.py                    # Shared fixtures and configuration
+├── test_api.py                    # API endpoint tests
+├── test_example_executor.py       # Example executor tests
+├── test_doc_sync_executor.py      # Documentation sync executor tests
+└── README.md                      # This file
+```
+
+## Running Tests
+
+### Run all tests
+```bash
+docker exec scheduler pytest
+```
+
+### Run with coverage report
+```bash
+docker exec scheduler pytest --cov=src --cov-report=term-missing
+```
+
+### Run specific test file
+```bash
+docker exec scheduler pytest tests/test_api.py
+```
+
+### Run specific test class
+```bash
+docker exec scheduler pytest tests/test_api.py::TestHealthEndpoint
+```
+
+### Run specific test
+```bash
+docker exec scheduler pytest tests/test_api.py::TestHealthEndpoint::test_health_endpoint_returns_healthy
+```
+
+### Run tests by marker
+```bash
+# Run only unit tests
+docker exec scheduler pytest -m unit
+
+# Run only API tests
+docker exec scheduler pytest -m api
+
+# Run only executor tests
+docker exec scheduler pytest -m executor
+
+# Run only fast tests (exclude slow)
+docker exec scheduler pytest -m "not slow"
+```
+
+### Run with verbose output
+```bash
+docker exec scheduler pytest -v
+```
+
+### Run with detailed failure output
+```bash
+docker exec scheduler pytest -vv --tb=long
+```
+
+### Stop on first failure
+```bash
+docker exec scheduler pytest -x
+```
+
+## Test Markers
+
+Tests are organized with pytest markers:
+
+- `@pytest.mark.unit` - Fast unit tests with no external dependencies
+- `@pytest.mark.integration` - Integration tests (may use database)
+- `@pytest.mark.api` - API endpoint tests
+- `@pytest.mark.executor` - Task executor tests
+- `@pytest.mark.slow` - Tests that take a while to run
+
+## Coverage Reports
+
+After running tests with coverage:
+
+- **Terminal**: Shows missing lines in terminal output
+- **HTML**: Open `htmlcov/index.html` in browser for detailed report
+- **JSON**: Machine-readable coverage data in `coverage.json`
+
+View HTML coverage report:
+```bash
+# From host machine
+open /home/jpmschweitzer/docker-data/scheduler/htmlcov/index.html
+```
+
+## Writing New Tests
+
+### Test File Naming
+- Test files must start with `test_`
+- Place in `tests/` directory
+- Use descriptive names: `test_<module_name>.py`
+
+### Test Function Naming
+- Test functions must start with `test_`
+- Use descriptive names: `test_<what_is_being_tested>`
+
+### Using Fixtures
+Fixtures are defined in `conftest.py`:
+
+```python
+def test_something(test_settings, auth_headers):
+    # Use fixtures as function parameters
+    assert test_settings.app_name == "Test Scheduler"
+```
+
+### Adding Markers
+```python
+@pytest.mark.unit
+@pytest.mark.api
+def test_health_endpoint(client):
+    response = client.get("/health")
+    assert response.status_code == 200
+```
+
+### Async Tests
+```python
+@pytest.mark.asyncio
+async def test_async_function():
+    result = await some_async_function()
+    assert result is not None
+```
+
+### Mocking
+```python
+from unittest.mock import patch, MagicMock
+
+def test_with_mock():
+    with patch('module.function') as mock_func:
+        mock_func.return_value = "mocked"
+        result = call_function_that_uses_it()
+        assert result == "mocked"
+```
+
+## Continuous Integration
+
+These tests are designed to run in CI pipelines:
+
+```yaml
+# Example GitHub Actions
+- name: Run tests
+  run: |
+    docker exec scheduler pytest --cov=src --cov-report=xml
+    docker exec scheduler pytest --cov=src --cov-report=html
+```
+
+## Test Database
+
+Tests use mocked database connections by default. For integration tests that require a real database:
+
+1. Set up a test database
+2. Use `POSTGRES_DB=test_scheduler` environment variable
+3. Run migrations before tests
+4. Clean up after tests
+
+## Troubleshooting
+
+### Tests fail with "ModuleNotFoundError"
+```bash
+# Install test dependencies
+docker exec scheduler /venv/bin/pip install -r requirements.txt
+```
+
+### Tests fail with database errors
+- Tests use mocked connections by default
+- Check that mocks are properly set up in conftest.py
+- For integration tests, ensure test database exists
+
+### Coverage not working
+```bash
+# Reinstall pytest-cov
+docker exec scheduler /venv/bin/pip install --upgrade pytest-cov
+```
+
+## Best Practices
+
+1. **Fast by default**: Unit tests should be fast (<1s each)
+2. **Isolated**: Tests should not depend on each other
+3. **Descriptive**: Test names should clearly describe what they test
+4. **Single assertion**: Test one thing per test when possible
+5. **Use fixtures**: Reuse common setup via fixtures
+6. **Mock external deps**: Don't hit real databases/APIs in unit tests
+7. **Mark appropriately**: Use markers to categorize tests
+
+## Current Coverage
+
+Run this to see current coverage:
+```bash
+docker exec scheduler pytest --cov=src --cov-report=term
+```
+
+Target: 80%+ code coverage for critical paths