LZ Kit

This package was created with the aim of boosting productivity for developers who are building innovative projects on LayerZero.

Getting Started

Prerequisites

Hardhat

LZ Kit was designed for a hardhat project so if you didn't setup hardhat, follow this tutorial first.

Hardhat Deploy

You also need hardhat-deploy plugin to run lz-kit test. Follow this link to install it.

Install

npm install -g @lz-asia/lz-kit

You need to import @lz-asia/lz-kit/hardhat in your hardhat.config.js or hardhat.config.ts:

import "@lz-asia/lz-kit/hardhat";

or

require("@lz-asia/lz-kit/hardhat");

Usage

Write a cross chain contract e.g. MyLzApp:

// contracts/MyLzApp.sol

pragma solidity ^0.8.0;

import "@layerzerolabs/solidity-examples/contracts/lzApp/LzApp.sol";

contract MyLzApp {
  constructor(address _lzEndpoint) LzApp(_lzEndpoint) {}

  // ... send and receive functions
}

Deployment script is needed:

// deploy/00_MyLzApp.ts

import { constants } from "ethers";
import { endpoint } from "../constants/layerzero.json";

export default async ({ getNamedAccounts, deployments, network }) => {
  const { deploy } = deployments;
  const { deployer } = await getNamedAccounts();

  await deploy("MyLzApp", {
    from: deployer,
    args: [endpoint[network.name]],
    log: true,
  });
};

Write a sample test script:

// test/MyLzApp.test.ts

import { utils } from "ethers";
import { srcChain, destChain } from "hardhat";

describe("MyLzApp", function () {
  it("should test", async function () {
    // your testing code
  });
});

Set environment variables for reuse:

INFURA_API_KEY=<your infura api key>
MNEMONIC=<your seed phrase>

Bootstrap ethereum, arbitrum and run cross chain tests:

lz-kit bootstrap -k "$INFURA_API_KEY" --mnemonic "$MNEMONIC" --balance 10000 --accounts 3 ethereum optimism arbitrum &&
lz-kit test -s ethereum-fork -d arbitrum-fork --mnemonic "$MNEMONIC" --deploy --config MyLzApp

Reference

lz-kit fork

It runs a hardhat node that forks a network at http://127.0.0.1:<port>. Default port is 8000 + (e.g. ethereum-fork: 8001, arbitrum-fork: 50161)

An example to fork ethereum and arbitrum:

lz-kit fork ethereum -k "$INFURA_API_KEY" &&
lz-kit fork optimism -k "$INFURA_API_KEY" &&
lz-kit fork arbitrum -k "$INFURA_API_KEY"

After forking, you'll see new config files under hardhat-configs/. We recommend you to add below to your .gitignore:

hardhat-configs/

As long as you keep those config files under hardhat-configs/, you have three additional hardhat networks ethereum-fork, optimism-fork and arbitrum-fork that you can use for testing, even if you didn't specify in your hardhat.config.js or hardhat.config.ts.

lz-kit relayer

It runs a relayer that read events from <source network> and calls lzReceive() of UA contracts on the destination networks.

An example to run relayer on three forked networks:

lz-kit relayer ethereum-fork --dest arbitrum-fork optimism-fork &&
lz-kit relayer optimism-fork --dest ethereum-fork arbitrum-fork &&
lz-kit relayer arbitrum-fork --dest ethereum-fork optimism-fork

Option --dest needs to be placed at the end of the command because it accepts variable number of networks.

lz-bootstrap

It first lz-kit fork networks, lz-kit relayer for them and sets balance for the first account of each network if needed.

An example to bootstrap all networks, set balance of three accounts of each network to 10000 ETH:

lz-kit bootstrap -k "$INFURA_API_KEY" --mnemonic "$MNEMONIC" --balance 10000 --accounts 3 ethereum optimism arbitrum

Network names need to be placed at the end of the command because it accepts variable number of networks.

lz-kit config

It sets trusted remotes for all combinations for given networks. The target contract must be a subclass of LzApp.

An example to config all forked networks:

lz-kit config --mnemonic "$MNEMONIC" ethereum-fork optimism-fork arbitrum-fork

Option --mnemonic specifies which account to be used when calling setTrustedRemoteAddress().

lz-kit test

It deploys and configures contracts if needed and run hardhat test with additional HRE objects srcChain and destChain.

It has dependency on hardhat-deploy plugin. Also you need to import @lz-asia/lz-kit/hardhat-plugin in your hardhat.config.js or hardhat.config.js.

An example to test cross chain contract on all combinations of forked networks:

lz-kit test -s ethereum-fork -d optimism-fork --mnemonic "$MNEMONIC" --deploy --config MyLzApp &&
lz-kit test -s ethereum-fork -d arbitrum-fork --mnemonic "$MNEMONIC" --deploy --config MyLzApp &&
lz-kit test -s optimism-fork -d ethereum-fork --mnemonic "$MNEMONIC" --deploy --config MyLzApp &&
lz-kit test -s optimism-fork -d arbitrum-fork --mnemonic "$MNEMONIC" --deploy --config MyLzApp &&
lz-kit test -s arbitrum-fork -d ethereum-fork --mnemonic "$MNEMONIC" --deploy --config MyLzApp &&
lz-kit test -s arbitrum-fork -d optimism-fork --mnemonic "$MNEMONIC" --deploy --config MyLzApp

In your test script, you can access srcChain and destChain as HRE objects. For example:

import { utils } from "ethers";
import { srcChain, destChain } from "hardhat";

describe("MyLzApp", function () {
  it("should test", async function () {
    const [deployer, alice, bob, carol] = await srcChain.getSigners();
  });
});

Chain object is defined as below:

interface SignerWithAddress extends Signer {
  address: string;
}

export interface Chain {
  name: string;
  config: HttpNetworkConfig;
  provider: providers.JsonRpcProvider;
  getSigners: () => Promise<Array<SignerWithAddress>>;
  getSigner: (address: string) => Promise<SignerWithAddress>;
  getImpersonatedSigner: (
    address: string,
    balance?: BigNumberish
  ) => Promise<SignerWithAddress>;
  getContract: <T extends Contract>(
    name: string,
    signer?: Signer
  ) => Promise<T>;
  getContractAt: <T extends Contract>(
    nameOrAbi: string | unknown[],
    address: string,
    signer?: Signer
  ) => Promise<T>;
}