coverage-analysis

# Test Coverage Analysis ## Running Coverage ```bash # Basic coverage report forge coverage # Output: # | File | % Lines | % Statements | % Branches | % Functions | # |--------------------|-----------------|-----------------|-----------------|-----------------| # | src/Vault.sol | 92.31% (36/39) | 89.47% (34/38) | 75.00% (12/16) | 100.00% (8/8) | # | src/Token.sol | 100.00% (12/12) | 100.00% (10/10) | 100.00% (4/4) | 100.00% (3/3) | ``` ## LCOV Output for Visualization ```bash # Generate lcov.info forge coverage --report lcov # View in VS Code with "Coverage Gutters" extension # Or generate HTML report: genhtml lcov.info -o coverage-report --branch-coverage open coverage-report/index.html ``` ## Coverage Types | Type | Meaning | Priority | |------|---------|----------| | **Line** | Was this line executed? | Medium | | **Statement** | Was this statement executed? | Medium | | **Branch** | Were both sides of if/else taken? | **High** | | **Function** | Was this function called? | Low | Branch coverage is the most important for security — untested branches are where bugs hide. ## Filtering Coverage ```bash # Exclude test files and scripts forge coverage --report lcov # Filter the lcov output lcov --remove lcov.info 'test/*' 'script/*' 'node_modules/*' \ --output-file lcov-filtered.info ``` ## Coverage-Driven Testing Workflow ### 1. Identify Gaps ```bash # Generate and inspect coverage forge coverage --report lcov genhtml lcov.info -o coverage-report --branch-coverage ``` ### 2. Focus on Uncovered Branches For each uncovered branch, write a targeted test: ```solidity // If coverage shows this branch is untested: // if (amount > maxDeposit) revert ExceedsMax(); function test_depositExceedsMax() public { uint256 maxDeposit = vault.maxDeposit(address(this)); vm.expectRevert(abi.encodeWithSelector(ExceedsMax.selector)); vault.deposit(maxDeposit + 1, address(this)); } ``` ### 3. Common Untested Paths ```solidity // Zero-amount edge cases function test_depositZero() public { vm.expectRevert("zero amount"); vault.deposit(0, address(this)); } // Reentrancy guard activation function test_reentrancyBlocked() public { attacker.setReentrancy(true); vm.expectRevert("ReentrancyGuard: reentrant call"); attacker.attack(); } // Overflow/underflow (checked math reverts) function test_overflowReverts() public { vm.expectRevert(); vault.deposit(type(uint256).max, address(this)); } // Access control all roles function test_onlyOwnerFunctions() public { vm.prank(nonOwner); vm.expectRevert(); vault.setFee(100); } // Pause/unpause paths function test_pausedDeposit() public { vault.pause(); vm.expectRevert("Pausable: paused"); vault.deposit(1 ether, address(this)); } ``` ## CI Integration ```yaml - name: Check coverage threshold run: | forge coverage --report summary | tee coverage.txt # Parse line coverage percentage COVERAGE=$(grep "| Total" coverage.txt | awk '{print $4}' | tr -d '%') if (( $(echo "$COVERAGE < 85" | bc -l) )); then echo "Coverage $COVERAGE% is below 85% threshold" exit 1 fi ``` ## Coverage Report in `foundry.toml` ```toml [profile.default] # Exclude from coverage analysis no_match_coverage = "test|script|mock" ``` ## Coverage Targets by Component | Component | Minimum | Target | |-----------|---------|--------| | Core protocol logic | 95% branch | 100% branch | | Token contracts | 90% branch | 100% branch | | Admin/governance | 85% branch | 95% branch | | Periphery/helpers | 80% branch | 90% branch | | View functions | 70% line | 85% line | ## Limitations - Coverage does not measure test quality — 100% coverage doesn't mean 100% correct - Foundry coverage doesn't handle inline assembly well - Branch coverage inside `require()` chains may not report correctly - Coverage overhead slows test execution (separate coverage CI step) - Unreachable code (dead branches) inflates uncovered percentage ## Checklist - [ ] `forge coverage` runs in CI on every PR - [ ] LCOV report generated for visual inspection - [ ] Branch coverage prioritized over line coverage - [ ] Coverage threshold enforced (85%+ for core contracts) - [ ] Test and script files excluded from coverage stats - [ ] Uncovered branches documented as known gaps or addressed - [ ] Coverage report reviewed during audit preparation - [ ] New features include tests that maintain/improve coverage