The stateful fuzz test revert by the HandlerStatefulFuzzCatches__UnsupportedToken

[ox1234]

I followed the course that do the stateful fuzz test. I followed Patrick's code to write the following code (i just paste the code from the lesson):

// SPDX-License-Identifier: MIT
pragma solidity 0.8.20;

import {HandlerStatefulFuzzCatches} from "src/invariant-break/HandlerStatefulFuzzCatches.sol";
import {Test} from "forge-std/Test.sol";
import {StdInvariant} from "forge-std/StdInvariant.sol";
import {MockUSDC} from "test/mocks/MockUSDC.sol";
import {YeildERC20} from "test/mocks/YeildERC20.sol";
import {IERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract AttemptedBreakTest is StdInvariant, Test {
    HandlerStatefulFuzzCatches handlerstatefulFuzzCatches;
    MockUSDC mockUSDC;
    YeildERC20 yeildERC20;
    uint256 startingAmount;

    IERC20[] supportedTokens;

    address user = makeAddr("user");

    function setUp() public {
        vm.startPrank(user);
        mockUSDC = new MockUSDC();
        yeildERC20 = new YeildERC20();
        startingAmount = yeildERC20.INITIAL_SUPPLY();
        mockUSDC.mint(user, startingAmount);
        vm.stopPrank();

        supportedTokens.push(IERC20(address(yeildERC20)));
        supportedTokens.push(IERC20(address(mockUSDC)));
        handlerstatefulFuzzCatches = new HandlerStatefulFuzzCatches(supportedTokens);
        targetContract(address(handlerstatefulFuzzCatches));
    }

    function testStartingAmount() public view {
        assert(startingAmount == mockUSDC.balanceOf(user));
        assert(startingAmount == yeildERC20.balanceOf(user));
    }

    function statefulFuzz_TestInvariantBreaks() public {
        vm.startPrank(user);
        handlerstatefulFuzzCatches.withdrawToken(IERC20(address(mockUSDC)));
        handlerstatefulFuzzCatches.withdrawToken(IERC20(address(yeildERC20)));
        vm.stopPrank();

        assert(handlerstatefulFuzzCatches.tokenBalances(user, IERC20(address(mockUSDC))) == 0);
        assert(handlerstatefulFuzzCatches.tokenBalances(user, IERC20(address(yeildERC20))) == 0);
        assert(mockUSDC.balanceOf(user) == startingAmount);
        assert(yeildERC20.balanceOf(user) == startingAmount);
    }
}

But when i run the statefulFuzz_TestInvariantBreaks test, it revert by the HandlerStatefulFuzzCatches__UnsupportedToken exception, which it calls the withdraw with an unknown ERC20 address:

But i check the code many times, i have no idea where the withdraw call is come from. Can somebody help me?

[ox1234]

Is that because the foundry use the random address to call the withdrawToken?

[EngrPips]

I think fuzzer used a random token, and that triggered the revert because the implementation contract does not recognize the token.

[ox1234]

Yes, i continue to see the lesson and i know that is called by the fuzzer and generate random address. Thank you for your answer, helps a lot!

[EngrPips]

Anytime, Friend. Keep crushing it.