Foundry Testing Best Practices

Fuzz Testing Strategy

1. Fuzz function inputs by default - When a test function has parameters, Foundry automatically fuzzes them
2. Use bound() over vm.assume - Prefer bound(value, min, max) to constrain inputs; vm.assume discards runs and wastes iterations
3. Apply Equivalence Class Partitioning - Only fuzz parameters that affect the code path under test. If a parameter doesn't change behavior, use a fixed representative value
4. Maximize bounds - Use the widest reasonable bounds to maximize coverage

// Good: bound with max range
amount = bound(amount, 1, type(uint96).max);

// Avoid: vm.assume wastes fuzz runs
vm.assume(amount > 0 && amount < type(uint96).max);

Test Organization