solidity-testing

name	solidity-testing
description	[AUTO-INVOKE] MUST be invoked BEFORE writing or modifying any test files (*.t.sol). Covers test structure, naming conventions, coverage requirements, fuzz testing, and Foundry cheatcodes. Trigger: any task involving creating, editing, or running Solidity tests.

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-test and --match-contract for 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