testing issues

    function withdraw() public onlyOwner {
        for (uint256 funderIndex=0; funderIndex < funders.length; funderIndex++){
            address funder = funders[funderIndex];
            addressToAmountFunded[funder] = 0;
        }
        funders = new address[](0);
        // // transfer
        // payable(msg.sender).transfer(address(this).balance);
        // // send
        // bool sendSuccess = payable(msg.sender).send(address(this).balance);
        // require(sendSuccess, "Send failed");
        // call
        (bool callSuccess, ) = payable(msg.sender).call{value: address(this).balance}("");
        require(callSuccess, "Call failed");
    }

Some q&a.