Testing Standards
Language Rule
- Always respond in the same language the user is using. If the user asks in Chinese, respond in Chinese. If in English, respond in English.
Test Organization
- One test contract per source contract:
MyToken.sol→MyToken.t.sol - File location: All tests in
test/directory - Naming:
test_<feature>_<scenario>for passing tests,testFail_<feature>_<scenario>for expected reverts
- Example: test_transfer_revertsWhenInsufficientBalance - Example: test_stake_updatesBalanceCorrectly
- Independence: Each test must run in isolation — use
setUp()for shared state, no cross-test dependencies - Filtering: Support
--match-testand--match-contractfor targeted runs
Coverage Requirements
Every core function must have tests covering:
| Scenario | What to verify |
|---|---|
| Happy path | Standard input → expected output, correct state changes |
| Permission checks | Unauthorized caller → vm.expectRevert with correct error |
| Boundary conditions | Zero values, max values (type(uint256).max), off-by-one |
| Failure scenarios | Every require / revert / custom error path |
| State changes | Storage updates, balance changes, event emissions (vm.expectEmit) |
| Edge cases | Empty arrays, duplicate calls, self-transfers |
Foundry Cheatcodes Quick Reference
| Cheatcode | Usage |
|---|---|
vm.prank(addr) | Next call from addr |
vm.startPrank(addr) | All calls from addr until vm.stopPrank() |
vm.warp(timestamp) | Set block.timestamp |
vm.roll(blockNum) | Set block.number |
vm.deal(addr, amount) | Set ETH balance |
vm.expectRevert(error) | Next call must revert with specific error |
vm.expectEmit(true,true,false,true) | Verify event emission (topic checks) |
vm.record() / vm.accesses() | Track storage reads/writes |
makeAddr("name") | Create labeled address for readable traces |
Fuzz Testing Rules
- All math-heavy and fund-flow functions must have fuzz tests
- Pattern:
function testFuzz_<name>(uint256 amount) public - Use
vm.assume()to constrain inputs:vm.assume(amount > 0 && amount < MAX_SUPPLY); - Default runs: 256 — increase to 10,000+ for critical functions:
forge test --fuzz-runs 10000
Common Commands
# Run all tests
forge test
# Run specific test function
forge test --match-test test_transfer
# Run specific test contract
forge test --match-contract MyTokenTest
# Verbose output with full trace
forge test -vvvv
# Gas report
forge test --gas-report
# Fuzz with more runs
forge test --fuzz-runs 10000
# Test coverage
forge coverage
# Coverage with report
forge coverage --report lcov