assertion error

[sahil-kaushik1]

        vm.prank(USER);
        basicnft.mintnft(dog);

        assert(basicnft.balanceOf(USER)==1);
        assert(keccak256(abi.encodePacked(dog)) == keccak256(abi.encodePacked(basicnft.tokenURI(0))));
        assert(USER==msg.sender);

    }```
    
    this is a test function 
    so on using the prank the msg.sender==USER  i guess?
    but the assertion is failing at last on comparing.
what could be the issue?

[EngrPips]

Hello @sahil-kaushik1, Do you know which of the assert is failing? Maybe rerun your test with the -vvvvv flag and share with us the stack trace of the test process

[sahil-kaushik1]

vm.startPrank(USER);
        basicnft.mintnft(dog);
        console.log(USER);
        console.log(msg.sender);
        assert(USER==msg.sender);
vm.stopPrank();

[EngrPips]

I see that inside the test contract, DefaultSender remains the msg.sender. I think you should read the vm.prank and vm.startPrank sections of the Foundry Book https://book.getfoundry.sh/cheatcodes/prank to understand properly how these cheat codes work. I assume that whenever you use vm.startPrank or vm.prank Foundry will only switch the msg.sender to the specified address just before it processes the transaction and at every other time the msg.sender in the test contract will normally be the DefaultSender but I am just trying to make sense of the situation you should read the docs to better understand how stuff works.

[sahil-kaushik1]

oki btw thanks for the help .
i will update if found the solution to this.

[LordAdhaar]

Hi @sahil-kaushik1,

From my understanding, msg.sender is the DefaultSender since you are calling it from the test. In the context of the test, msg.sender is the DefaultSender.

If you were to put a console.log(msg.sender) inside the basicnft.mint() function, you would get the msg.sender as USER because the msg.sender == USER in the context of the basicnft.mint() function.

However, for the test, the msg.sender == DefaultSender.

[EngrPips]

Make sense