test-factory-patterns

Test factories are functions that generate multiple realistic instances of data for testing. Build factories under /test/*Factory.ts that produce 3-5 varied instances with plausible field values, supporting partial overrides so tests can customize data while preserving sensible defaults.

Factory functions reduce test brittleness by generating varied, realistic data instead of reusing identical static fixtures. This improves test coverage, makes tests less dependent on specific hardcoded values, and better reflects production data scenarios.

Yes. Test factories support partial overrides, letting you customize specific fields while the factory provides sensible defaults for the rest. This keeps tests maintainable while allowing fine-grained control when needed.

Organize factories in /test/*Factory.ts files with consistent naming and structure across your test suite. Each factory should generate realistic instances with varied field values that reflect actual production data patterns.

Factories generate realistic, varied data instances with sensible defaults and override support. Mocks typically replace entire objects or services. Factories are best for populating test data; mocks are better for isolating dependencies during unit tests.

Yes. Factory functions in TypeScript can enforce type safety while generating realistic mock data. Structuring factories in dedicated files ensures type-aware overrides and maintains consistency across your test suite.