How can i construct Unit testing for smart contract?

Question

Because i need to test smart contracts functions deployed in ropsten

function deposit(uint256 _amount) public {
        // Amount must be greater than zero
        require(_amount > 0, "amount cannot be 0");
    
        // Transfer MyToken to smart contract
        token.safeTransferFrom(msg.sender, address(this), _amount);
    
        // Mint FarmToken to msg sender
        _mint(msg.sender, _amount);
    }

Answer 1

For unit testing smart contracts have a look at Truffle:

https://www.trufflesuite.com/docs/truffle/testing/testing-your-contracts

Answer 2

You would use a framework that provide all the tools necessary for that. A year ago, I would've suggested to use Truffle for that. But now, I would suggest you should instead give Hardhat a try as it's doing things much better and is aiming to make smart contract development headache-free.

Those frameworks would provide you with everything you would need for your blockchain dev experience, and not just testing.