DssVest_fuzz_failures_debug_tests.sol

// Add these tests into DssVest.t.sol

    uint256 constant WAD = 10**18;
    function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require((z = x + y) >= x);
    }
    function testFuzzFail_1() public {
        // derived from echidna failure:
        // test_init_ids(115792089237316195423570985008687907853269984665640564039457584007913129639935,100242773934347682338375481833561433633362664707040856359631189992494487309630,10,39080061795132864699069909921915714851660400468839437511646123280429906730201,1524785992,0x20000)

        uint256 _amt = 115792089237316195423570985008687907853269984665640564039457584007913129639935;
        uint256 _bgn = 100242773934347682338375481833561433633362664707040856359631189992494487309630;
        uint256 _tau = 10;
        uint256 _clf = 39080061795132864699069909921915714851660400468839437511646123280429906730201;
        uint256 _pmt = 1524785992;
        address _mgr = address(0x20000);

        _amt = _amt < WAD ? _amt *= WAD : _amt % uint128(-1);
        _bgn = block.timestamp + _bgn % vest.MAX_VEST_PERIOD();
        _tau = 1 + _tau % vest.MAX_VEST_PERIOD();
        _clf = _clf % _tau;

// added to confirm hypothesis
//        assertTrue(_amt > 0);

        _pmt = _pmt % _amt;
        uint256 prevId = vest.ids();
        uint256 id = vest.init(address(this), _amt, _bgn, _tau, _clf, _pmt, _mgr);
        assert(vest.ids() == add(prevId, id));
        assert(vest.valid(id));
    }
    
    function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require((z = x - y) <= x);
    }
    function testFuzzFail_2() public {
        // derived from echidna failure:
        // test_vest(0,0,1,1,0,0x0)
        // test_init_ids(0,0,0,0,0,0x0)

        uint256 _amt = 0;
        uint256 _bgn = 0;
        uint256 _tau = 1;
        uint256 _clf = 1;
        uint256 _pmt = 0;
        address _mgr = address(0);

        _amt = _amt % uint128(-1);
        if (_amt < WAD) _amt = (1 + _amt) * WAD;
        _bgn = block.timestamp + _bgn % vest.MAX_VEST_PERIOD();
        _tau = 1 + _tau % vest.MAX_VEST_PERIOD();
        _clf = _clf % _tau;
        _pmt = _pmt % _amt;
        uint256 id = vest.init(address(this), _amt, _bgn, _tau, _clf, _pmt, _mgr);
        assert(vest.valid(id));
{
        uint256 ids = vest.ids();
        vest.vest(id);
        (address usr, uint48 bgn, uint48 clf, uint48 fin, uint128 amt, uint128 rxd, address mgr) = vest.awards(id);
        if (block.timestamp >= fin) {
          assert (vest.ids() == sub(ids, 1));
        } else if (block.timestamp >= clf) {
          uint256 t = (block.timestamp - bgn) * WAD / (fin - bgn);
          assert(t >= 0);
          assert(t < WAD);
          uint256 mkr = (amt * t) / WAD;
          assert(mkr >= 0);
          assert(mkr < amt);
          assert(rxd == uint128(mkr));
        }
}

        _amt = 0;
        _bgn = 0;
        _tau = 0;
        _clf = 0;
        _pmt = 0;
        _mgr = address(0);

        _amt = _amt % uint128(-1);
        if (_amt < WAD) _amt = (1 + _amt) * WAD;
        _bgn = block.timestamp + _bgn % vest.MAX_VEST_PERIOD();
        _tau = 1 + _tau % vest.MAX_VEST_PERIOD();
        _clf = _clf % _tau;
        _pmt = _pmt % _amt;
        uint256 prevId = vest.ids();
        id = vest.init(address(this), _amt, _bgn, _tau, _clf, _pmt, _mgr);
// added to confirm hypothesis
/*
        assertEq(vest.ids(), 2);
        assertEq(prevId, 1);
        assertEq(id, 2);
*/
        assert(vest.ids() == add(prevId, id));
        assert(vest.valid(id));
    }