test.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.0;

contract YouDeposit {

    mapping(address => uint) balances;

    function deposit() public payable {
        require(msg.value > 0, "No value sent");
        balances[msg.sender] += msg.value;
    }

    function userBalance(address _user) external view returns(uint) {
        return balances[_user];
    }

    receive() external payable {
        deposit();
    }

    function withdraw() public {
        require(balances[msg.sender] > 0, "No stake");
        payable(msg.sender).transfer(balances[msg.sender]);
    }
}