TSwap approve function

[Shawon-Mandal]

I am currently writing the TSwap invariant tests along with the course.
In the setUP function of invariant.t.sol there are these lines

        poolToken.approve(address(pool), type(uint256).max);
        weth.approve(address(pool), type(uint256).max);
        

I could not find any approve function in TSwapPool.sol but this approve was
found after running forge inspect TSwapPool methods command in the terminal.

In short, if there is no approve function in the original TSwapPool.sol is it
mandatory to approve them inside the invariant test suite? if yes, then why?

Thank you

[EngrPips]

Hello @Shawon-Mandal, I am not sure I correctly understand your question, but we are doing those two approvals because we want to send some poolToken and weth to the pool. Since both poolTokenand weth are ERC20, we need to call the approve function on them to approve the address of the TSWAP pool to take our token. Doing so ensures that the transaction successfully goes through whenever we call a function to supply liquidity to the TSWAP pool

[Shawon-Mandal]

I see. I was confused at first to see that when I wrote the forge inspect TSwapPool methods inside my terminal, I saw this output

I thought that the approve function belonged to TSwapPool.sol contract due to the reason that TSwapPool was mentioned in the command. Now I realize that it was actually a function of ERC20.sol

[EngrPips]

I am glad you realize it now. Keep crushing it, friend.