dAppetter

E2E testing for dApps using Puppeteer + MetaMask

Installation

$ npm i @sriharikapu/dappetter

Usage

import puppeteer from 'puppeteer'
import dappetter from '@sriharikapu/dappetter'

async function main() {
  const browser = await dappetter.launch(puppeteer)
  const metamask = await dappetter.getMetamask(browser)

  // create or import an account
  // await metamask.createAccount()
  await metamask.importAccount('already turtle birth enroll since...')

  // you can change the network if you want
  await metamask.switchNetwork('ropsten')

  // go to a dapp and do something that prompts MetaMask to confirm a transaction
  const page = await browser.newPage()
  await page.goto('http://my-dapp.com')
  const payButton = await page.$('#pay-with-eth')
  await payButton.click()

  // 🏌
  await metamask.confirmTransaction()
}

main()

API

• dappetter.launch(puppeteer[, launchOptions]): returns an instance of browser, same as puppeteer.launch, but it also installs the MetaMask extension. It supports all the regular puppeteer.launch options as a second argument with the addition of two extra ones:

  • metamaskPath: Path to the MetaMask extension (by default it uses the one bundled)

  • extensionUrl: URL of the MetaMask extension, by default it is chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/popup.html but if you use a different version you might need to change it use the right extension id.

• dappetter.getMetaMask(browser): returns a promise that resolves to an object that allows you to interact with MetaMask by using the following methods:

  • metamask.createAccount([password]): it commands MetaMask to create a new account, it resolves when it's done. It can only be used while you haven't signed in yet, otherwise it throws. The password is optional, it defaults to password1234.

  • metamask.importAccount(seed[, password]): it commands MetaMask to import an account, you need to provide the twelve words seed. It can only be used while you haven't signed in yet, otherwise it throws. The password is optional, it defaults to password1234.

  • metamask.switchAccount(accountIndex): it commands MetaMask to switch to a different account, by passing the index/position of the account in the accounts list.

  • metamask.importPK(privateKey): it commands MetaMask to import an private key. It can only be used while you haven't signed in yet, otherwise it throws.

  • metamask.lock(): signs out from MetaMask. It can only be used if you arelady signed it, otherwise it throws.

  • metamask.unlock([password]): it unlocks the MetaMask extension. It can only be used in you locked/signed out before, otherwise it throws. The password is optional, it defaults to password1234.

  • metamask.switchNetwork(networkName): it changes the current selected network. networkName can take the following values: "main", "ropsten", "rinkeby", "kovan", "localhost".

  • metamask.addNetwork(url): it adds a custom network to MetaMask.

  • metamask.confirmTransaction([{ gas, gasLimit }]): commands MetaMask to submit a transaction. For this to work MetaMask has to be in a transaction confirmation state (basically promting the user to submit/reject a transaction). You can (optionally) pass an object with gas and/or gasLimit, by default they are 20 and 50000 respectively.

  • metamask.sign(): commands MetaMask to sign a message. For this to work MetaMask must be in a sign confirmation state.

  • metamask.approve({ allAccounts }): confirm Dapp permissions to use Metamask account. If you plan to use the Dapp with multiple accounts you can use allAccounts to add permission to all imported accounts. By default is false