attac-t Skill: Craft Test Factory
"The power of a factory is not the complexity of the code, but rather one or two patterns properly applied."
The Standard
- Static
new()Constructor: Entry point. Returns fresh instance. - Immutability via Clone: State methods return cloned instance, never mutate.
- Auto-Increment Uniques: Static counter for unique fields like invoice numbers.
- Beyond Models: Create DTOs, events, requests—anything tests need.
The Anti-Patterns
| ❌ Don't | ✅ Do | Why |
|---|---|---|
| Mutable state | Clone on every modifier | Prevents test pollution |
| Random unique values | Static incrementing counter | Deterministic, debuggable |
| Laravel factory only | Custom factories too | DTOs need factories too |
| Inline test setup | Named factory states | Self-documenting tests |
Real-World Examples
See examples.md.