Function: externalSwap(address approveTarget, address swapTarget, address fromToken, address toToken, uint256 fromAmount, uint256 minToAmount, address payable to, bytes data)

Performs a swap between two tokens using external (i.e., not WOOFI) swapTarget.

Inputs

• approveTarget

  • Control: Fully controlled by the caller.

  • Constraints: Has to be whitelisted.

  • Impact: The address to approve tokens for.

• swapTarget

  • Control: Fully controlled by the caller.

  • Constraints: Has to be whitelisted.

  • Impact: The address that swaps the tokens.

• fromToken

  • Control: Fully controlled by the caller.

  • Constraints: msg.sender needs to have enough balance.

  • Impact: The token to swap from.

• toToken

  • Control: Fully controlled by the caller.

  • Constraints: address(this) needs to have enough balance.

  • Impact: The token to swap to.

• fromAmount

  • Control: Fully controlled by the caller.

  • Constraints: msg.sender needs to have enough balance of fromToken.

  • Impact: The amount of fromToken to swap.

• minToAmount

  • Control: Fully controlled by the caller.

  • Constraints: Checked that the returned toTokens are greater than or equal to this value.

  • Impact: The minimum amount of toToken to receive.

• to

  • Control: Fully controlled by the caller.

  • Constraints: None. Checked that it is not the zero address.

  • Impact: The destination address to send the swapped tokens to.

• data

  • Control: Fully controlled by the caller.

  • Constraints: None.

  • Impact: The data to pass to the swapTarget.

Branches and code coverage

Intended branches

• Ensure that approveTarget is not the zero address.

  Test coverage

• Ensure that swapTarget is not the zero address.

  Test coverage

• Ensure that fromToken is not the zero address.

  Test coverage

• Ensure that toToken is not the zero address.

  Test coverage

• Ensure that to is not the zero address.

  Test coverage

• Ensure that approveTarget is whitelisted.

  Test coverage

• Ensure that swapTarget is whitelisted.

  Test coverage

• If fromToken is not ETH, transfer fromAmount from the msg.sender and approve it to approveTarget.

  Test coverage

• Call swapTarget with the provided data that facilitates the swap.

  Test coverage

• Ensure the swap call was successful.

  Test coverage

• Assure that the post balance of toToken is greater than or equal to the pre balance.

  Test coverage

• Ensure that the realToAmount is greater than or equal to the minToAmount and greater than zero.

  Test coverage

• Forward the recently swapped tokens to the to address.

  Test coverage

Negative behavior

• Should not reenter.

  Negative test