a16z/erc4626-tests

ERC4626 Property Tests

erc4626-tests's Issues

Use previewMint + mint in setUpVault

erc4626-tests/ERC4626.test.sol

Lines 36 to 39 in 8b1d7c2

	uint shares = init.share[i];
	try IMockERC20(_underlying_).mint(user, shares) {} catch { vm.assume(false); }
	_approve(_underlying_, user, _vault_, shares);
	vm.prank(user); try IERC4626(_vault_).deposit(shares, user) {} catch { vm.assume(false); }

The tests are assuming the vault starts at 1:1 price. The following would be more general:

uint shares = init.share[i];
uint assets = IERC4626(_vault_).previewMint(shares);
try IMockERC20(_underlying_).mint(user, assets) {} catch { vm.assume(false); } 
_approve(_underlying_, user, _vault_, assets); 
vm.prank(user); try IERC4626(_vault_).mint(shares, user) {} catch { vm.assume(false); } 

maxDeposit() implements a upper bound: test fails with "The `vm.assume` cheatcode rejected too many inputs"

We are integrating the property test suite as part of the verification of our vault contracts. Unfortunately all tests are failing with the following error:

Test result: FAILED. 0 passed; 1 failed; finished in 15.18s

Failing tests:
Encountered 1 failing test in contracts/test/ERC4626StdTest.sol:ERC4626StdTest
[FAIL. Reason: The `vm.assume` cheatcode rejected too many inputs (65536 allowed)] test_maxDeposit((address[4],uint256[4],uint256[4],int256)) (runs: 22, μ: 447892, ~: 465089)

Encountered a total of 1 failing tests, 0 tests succeeded

I figured that the problem might be related to the fixed upper boud in the maxDeposit() of the function. The function is implemented to limit the number of assets in the vault. Removing the bound let the test pass, but it does not make sense w.r.t to the contract's logic.

function maxDeposit(address) public view override returns (uint256) {
    if (totalAssets() > MAX_TOTAL_ASSETS) {
        return 0;
    }
    return MAX_TOTAL_ASSETS - IERC20(asset()).balanceOf(address(this));
}

Is it possible to bound the "assets" value in fuzzer? For example, an input of 4888566203988820057829237745407778857278425300380918631855130364758515 does not make sense in our case.

[470198] ERC4626StdTest::test_maxDeposit(([0xabAde514b7e828bD42Cb5272b26F2ebBbDa794F0, 0x5D32577cCD88F4c9D850dAD9D4A28ec7F23D963e, 0x683eF4386bbec40e87bF86e2181193Cf91c495AD, 0xbE411Fe80fd84Fe87F69b5356Bd74f8Ce5276EEf], [22698694737177962168034904413051506502332361420, 4888566203988820057829237745407778857278425300380918631855130364758515, 56852593677044934, 32556299], [2692848953710946714442091, 0, 17461643070425363004, 5566649], 0))

Thanks!