writing-foundry-tests

To write Foundry tests, use testFuzz_ for fuzzing and invariant_ prefixes to enforce global contract health. Apply handler-based fuzzing to catch deep edge cases and maintain contract state integrity.

Standard Foundry test naming conventions require test_ for unit tests, testFuzz_ for fuzz tests, and invariant_ for invariant checks. Following these prefixes ensures readable testing patterns and reliable CI outcomes.

Use Foundry cheatcodes like vm.prank to mock caller addresses and vm.expectRevert to assert revert conditions. Apply makeAddr and deal to set up isolated test environments with predictable state modifications.

Structure Foundry test isolation by implementing the setUp function to initialize fresh contract instances for each test. This ensures deterministic behavior and prevents state leakage across different test cases.

Yes, handler-based fuzzing in Foundry allows you to test deep edge cases by routing random inputs through constrained handler functions. This approach maintains global invariants and catches complex state-dependent vulnerabilities.

Foundry tests often fail in CI due to non-deterministic state or improper fuzzing bounds. Enforce strict test isolation via setUp, constrain fuzzing inputs, and use vm.expectRevert to ensure safe revert expectations.