## Account Abstraction Lesson 10: Unsigned `PackedUserOperation` Test Welcome to our 10th lesson on **Account Abstraction**. In the previous lesson, we tested the `execute` function of our `MinimalAccount`. Now we need to set up the test for `validateUserOp`, which includes: - `PackedUserOperation` - `userOpHash` - `missingAccountFunds` But before we can do any of this, we will need to write another script. This lesson will allow us to do this by: - setting up our essential code layout. - beginning the code for two important functions: - `generateSignedUserOperation` - `_generateUnsignedUserOperation` --- ### Writing Our SendPackedUserOp Script First, we are going to write a script that will help us generate the data for the `PackedUserOperation` and sign it. We can do this directly in our `MinimalAccountTest.t.sol`. However, it would be more beneficial to create in our `SendPackedUserOp` script. Let's set up the essential code and also comment some steps for further building. **<span style="color:red">SendPackedUserOp.s.sol</span>** ```js // SPDX-License-Identifier: MIT pragma solidity 0.8.24; import {Script} from "forge-std/Script.sol"; import {PackedUserOperation} from "lib/account-abstraction/contracts/interfaces/PackedUserOperation.sol"; contract SendPackedUserOp is Script { function run() public {} function generateSignedUserOperation(bytes memory callData) public view returns (PackedUserOperation memory) { // Step 1. Generate the unsigned data // Step 2. Sign and return it } } ``` For step 1, we are going to create a separate function called `_generateUnsignedUserOperation`. It will take `bytes memory calldata`, `address sender`, and `uint256 nonce`. It will populate all the fields of the `PackedUserOperation` except for the signature. We will also need some variables for gas limits. ```js function _generateUnsignedUserOperation(bytes memory callData) internal pure returns (PackedUserOperation memory) { uint128 verificationGasLimit = 16777216; uint128 callGasLimit = verificationGasLimit; uint128 maxPriorityFeePerGas = 256; uint128 maxFeePerGas = maxPriorityFeePerGas; return PackedUserOperation({ sender: sender, nonce: nonce, initCode: hex"", callData: callData, accountGasLimits: bytes32(uint256(verificationGasLimit) << 128 | callGasLimit), preVerificationGas: verificationGasLimit, gasFees: bytes32(uint256(maxPriorityFeePerGas) << 128 | maxFeePerGas), paymasterAndData: hex"", signature: hex"" }); } ``` > ❗ **NOTE** Gas fees and limits don't have to make sense at this point. Now we can use our `_generateUnsignedUserOperation` function for step 1 of our `generateSignedUserOperation` function. ```js function generateSignedUserOperation(bytes memory callData, address sender) public view returns (PackedUserOperation memory) { // Step 1. Generate the unsigned data uint256 nonce = vm.getNonce(sender); PackedUserOperation memory unsignedUserOp = _generateUnsignedUserOperation(callData, sender, nonce); // Step 2. Sign and return it } ``` That's a wrap for this lesson, but we aren't done with our script yet. Take a moment to go reflect on what we've done so far. Move on to the next lesson when you are ready.