test-data-management

name	test-data-management
description	Creating and managing test data via fixtures, builders, factories, and minimal realistic datasets.

Test Data Management

Strategies for creating and maintaining test data.

Context

You are designing test data infrastructure. Good test data is realistic but lightweight.

Domain Context

• Fixtures: Pre-built test data sets; inflexible but fast
• Builders: Fluent API to construct objects; flexible, readable
• Factories: Methods that generate test data; reusable, minimal
• Realistic: Use production-like data; but omit sensitive info
• Minimal: Only data relevant to the test; avoid clutter

Instructions

1. Choose Strategy: Fixtures (pre-built), Builders (flexible), Factories (reusable)
2. Use Builders for Complex Objects: Clear intent; easy to vary specific fields
3. Create Factories for Common Patterns: User factory, Order factory
4. Avoid Shared State: Each test gets fresh data; no pollution
5. Seed Data Carefully: Use realistic but non-sensitive data
6. Document Defaults: Default builder state should be valid for most tests
7. Performance: Consider test database resets vs. transactions for cleanup

Anti-Patterns

• Massive fixture files with hundreds of records; hard to understand which data matters
• Global shared test data; tests interfere with each other
• Over-realistic test data (full names, addresses); wastes resources
• Complex object construction in tests; use builders instead
• Test data stored in files separate from tests; couples tests to external state

Further Reading

• Gerard Meszaros, xUnit Test Patterns, on Test Fixture Strategies
• Roy Osherove, The Art of Unit Testing, on Test Data