Database fixture patterns in PyTest - Framework Patterns

Framework Mode - Database fixture patterns

Folder Structure

tests/
├── test_users.py
├── test_orders.py
├── conftest.py

fixtures/
├── db_fixtures.py

utils/
├── db_helpers.py

config/
├── config.yaml

Test Framework Layers

• Fixtures Layer: Contains database setup and teardown code using pytest fixtures (e.g., db_fixtures.py).
• Test Layer: Test files in tests/ use fixtures to prepare database state before running tests.
• Utilities Layer: Helper functions for database operations like connecting, cleaning, or seeding data (db_helpers.py).
• Configuration Layer: Holds environment settings such as database URLs and credentials (config.yaml).

Configuration Patterns

• Use a config.yaml file to store database connection strings for different environments (dev, test, prod).
• Load configuration in conftest.py to provide fixtures with environment-specific settings.
• Use environment variables to override sensitive data like passwords.
• Allow command-line options in pytest to select environment or database type.

Test Reporting and CI/CD Integration

• Use pytest built-in reporting with --junitxml=report.xml for CI systems.
• Integrate with CI tools (GitHub Actions, Jenkins) to run tests on database fixtures automatically.
• Ensure database is reset or migrated before tests run in CI to keep tests isolated.
• Use pytest plugins like pytest-html for readable HTML reports.

Best Practices

• Isolate Tests: Use fixtures to create fresh database state for each test to avoid side effects.
• Use Scoped Fixtures: Use function scope for tests needing clean state, session scope for expensive setup.
• Clear Data After Tests: Always clean or rollback changes after tests to keep database consistent.
• Parameterize Fixtures: Allow fixtures to accept parameters to reuse setup for different test scenarios.
• Keep Fixtures Simple: Avoid complex logic inside fixtures; delegate to helper functions.

Self Check

Where would you add a new fixture that sets up a test user in the database?

Key Result

Use pytest fixtures to manage database setup and teardown for isolated, repeatable tests.