flashloan-rs 0.2.3

Minimal Multicall3 Flashloan Module
Documentation
// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity >=0.8.0;

import {DSTest} from "ds-test/test.sol";

import {Hevm} from "./Hevm.sol";

/// @notice Extended testing framework for DappTools projects.
/// @author Solmate (https://github.com/transmissions11/solmate/blob/main/src/test/utils/DSTestPlus.sol)
contract DSTestPlus is DSTest {
    Hevm internal constant hevm = Hevm(HEVM_ADDRESS);

    address internal constant DEAD_ADDRESS = 0xDeaDbeefdEAdbeefdEadbEEFdeadbeEFdEaDbeeF;

    string private checkpointLabel;
    uint256 private checkpointGasLeft = 1; // Start the slot warm.

    modifier brutalizeMemory(bytes memory brutalizeWith) {
        /// @solidity memory-safe-assembly
        assembly {
            // Fill the 64 bytes of scratch space with the data.
            pop(
                staticcall(
                    gas(), // Pass along all the gas in the call.
                    0x04, // Call the identity precompile address.
                    brutalizeWith, // Offset is the bytes' pointer.
                    64, // Copy enough to only fill the scratch space.
                    0, // Store the return value in the scratch space.
                    64 // Scratch space is only 64 bytes in size, we don't want to write further.
                )
            )

            let size := add(mload(brutalizeWith), 32) // Add 32 to include the 32 byte length slot.

            // Fill the free memory pointer's destination with the data.
            pop(
                staticcall(
                    gas(), // Pass along all the gas in the call.
                    0x04, // Call the identity precompile address.
                    brutalizeWith, // Offset is the bytes' pointer.
                    size, // We want to pass the length of the bytes.
                    mload(0x40), // Store the return value at the free memory pointer.
                    size // Since the precompile just returns its input, we reuse size.
                )
            )
        }

        _;
    }

    function startMeasuringGas(string memory label) internal virtual {
        checkpointLabel = label;

        checkpointGasLeft = gasleft();
    }

    function stopMeasuringGas() internal virtual {
        uint256 checkpointGasLeft2 = gasleft();

        // Subtract 100 to account for the warm SLOAD in startMeasuringGas.
        uint256 gasDelta = checkpointGasLeft - checkpointGasLeft2 - 100;

        emit log_named_uint(string(abi.encodePacked(checkpointLabel, " Gas")), gasDelta);
    }

    function fail(string memory err) internal virtual {
        emit log_named_string("Error", err);
        fail();
    }

    function assertFalse(bool data) internal virtual {
        assertTrue(!data);
    }

    function assertUint128Eq(uint128 a, uint128 b) internal virtual {
        assertEq(uint256(a), uint256(b));
    }

    function assertUint64Eq(uint64 a, uint64 b) internal virtual {
        assertEq(uint256(a), uint256(b));
    }

    function assertUint96Eq(uint96 a, uint96 b) internal virtual {
        assertEq(uint256(a), uint256(b));
    }

    function assertUint32Eq(uint32 a, uint32 b) internal virtual {
        assertEq(uint256(a), uint256(b));
    }

    function assertBoolEq(bool a, bool b) internal virtual {
        b ? assertTrue(a) : assertFalse(a);
    }

    function assertApproxEq(
        uint256 a,
        uint256 b,
        uint256 maxDelta
    ) internal virtual {
        uint256 delta = a > b ? a - b : b - a;

        if (delta > maxDelta) {
            emit log("Error: a ~= b not satisfied [uint]");
            emit log_named_uint("  Expected", b);
            emit log_named_uint("    Actual", a);
            emit log_named_uint(" Max Delta", maxDelta);
            emit log_named_uint("     Delta", delta);
            fail();
        }
    }

    function assertRelApproxEq(
        uint256 a,
        uint256 b,
        uint256 maxPercentDelta // An 18 decimal fixed point number, where 1e18 == 100%
    ) internal virtual {
        if (b == 0) return assertEq(a, b); // If the expected is 0, actual must be too.

        uint256 percentDelta = ((a > b ? a - b : b - a) * 1e18) / b;

        if (percentDelta > maxPercentDelta) {
            emit log("Error: a ~= b not satisfied [uint]");
            emit log_named_uint("    Expected", b);
            emit log_named_uint("      Actual", a);
            emit log_named_decimal_uint(" Max % Delta", maxPercentDelta, 18);
            emit log_named_decimal_uint("     % Delta", percentDelta, 18);
            fail();
        }
    }

    function assertBytesEq(bytes memory a, bytes memory b) internal virtual {
        if (keccak256(a) != keccak256(b)) {
            emit log("Error: a == b not satisfied [bytes]");
            emit log_named_bytes("  Expected", b);
            emit log_named_bytes("    Actual", a);
            fail();
        }
    }

    function assertUintArrayEq(uint256[] memory a, uint256[] memory b) internal virtual {
        require(a.length == b.length, "LENGTH_MISMATCH");

        for (uint256 i = 0; i < a.length; i++) {
            assertEq(a[i], b[i]);
        }
    }

    function bound(
        uint256 x,
        uint256 min,
        uint256 max
    ) internal virtual returns (uint256 result) {
        require(max >= min, "MAX_LESS_THAN_MIN");

        uint256 size = max - min;

        if (size == 0) result = min;
        else if (size == type(uint256).max) result = x;
        else {
            ++size; // Make max inclusive.
            uint256 mod = x % size;
            result = min + mod;
        }

        emit log_named_uint("Bound Result", result);
    }

    function min3(
        uint256 a,
        uint256 b,
        uint256 c
    ) internal pure returns (uint256) {
        return a > b ? (b > c ? c : b) : (a > c ? c : a);
    }

    function min2(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? b : a;
    }
}