# Swap Exercises In this exercise, you'll learn how to swap tokens with the [`PoolManager`](https://github.com/Uniswap/v4-core/blob/main/src/PoolManager.sol) contract. The starter code for this exercise is provided in [`foundry/src/exercises/Swap.sol`](https://github.com/Cyfrin/defi-uniswap-v4/blob/main/foundry/src/exercises/Swap.sol) Solution is in [`foundry/src/solutions/Swap.sol`](https://github.com/Cyfrin/defi-uniswap-v4/blob/main/foundry/src/solutions/Swap.sol) ## Task 1 - Initiate a swap ```solidity function swap(SwapExactInputSingleHop calldata params) external payable { // Write your code here } ``` - Determine the currency to take from the caller and transfer it into the contract. - Unlock the `PoolManager` contract. - Refund any remaining currency that was taken from the caller. ## Task 2 - Unlock callback ```solidity function unlockCallback(bytes calldata data) external onlyPoolManager returns (bytes memory) { // Write your code here return ""; } ``` - Swap currencies with the `PoolManager` contract. - Revert if amount out is less than the minimum specified (`SwapExactInputSingleHop.amountOutMin`) ## Test ```shell forge test --fork-url $FORK_URL --match-path test/Swap.test.sol -vvv ```