Add support for `msgSender` function in `PoolSwapTest`

[mikeghen]

Component

No response

Describe the suggested feature and problem it solves.

I was working on dynamic fees and needed to get the msgSender for my tests. While this function is documented, it does not currently exist inPoolSwapTest.

Describe the desired implementation.

Here is a suggestion, perhaps there is another way.

contract PoolSwapTest is PoolTestBase {
    ...

    address internalMsgSender;

    constructor(IPoolManager _manager) PoolTestBase(_manager) {}
    
    ...

    function setMsgSender(address newMsgSender) external {
        internalMsgSender = newMsgSender;
    }

    function msgSender() external view returns (address) {
        return internalMsgSender;
    }
}

Describe alternatives.

No response

Additional context.

No response

[linear]

PROTO-798 Add support for `msgSender` function in `PoolSwapTest`

[Pybast]

This would be very useful indeed as most public routers have this functionality and it's use is described in the official doc here.

For reference, this is the implementation on the UniversalRouter (might be worth simplifying it for PoolSwapTest contract but we should aim to match all functionalities of the official router I imagine). I can work on a PR if this is needed.

https://github.com/Uniswap/universal-router/blob/3663f6db6e2fe121753cd2d899699c2dc75dca86/contracts/base/Dispatcher.sol#L34-L39