Playwright Wallet Mock TS

A TypeScript library for mocking Web3 browser wallets (like MetaMask) in Playwright tests. This package provides a simple way to simulate wallet interactions in your dApp tests.

Features

• Mock Ethereum wallet (MetaMask-like) in Playwright tests
• Support for EIP-1193 standard
• Local API server for making wallet requests
• Automatic port allocation for the API server
• TypeScript support

Installation

npm install @finn_gal/playwright-wallet-mock-ts

Usage

Basic Usage

import { chromium } from "playwright";
import { installMockWallet } from "@finn_gal/playwright-wallet-mock-ts";
import { privateKeyToAccount } from "viem/accounts";
import { mainnet } from "viem/chains";
import { http } from "viem";

async function testDapp() {
  const browser = await chromium.launch({
    headless: false,
  });
  const context = await browser.newContext();
  const page = await context.newPage();
  
  // Install the mock wallet
  await installMockWallet({
    page,
    account: privateKeyToAccount(
      "0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80", // Example private key (don't use in production)
    ),
    defaultChain: mainnet,
    transports: { [mainnet.id]: http() },
    debug: true,
  });

  // Navigate to your dApp
  await page.goto("https://your-dapp-url.com");
  
  // Your wallet is now available in the page as window.ethereum
  // You can interact with your dApp as if MetaMask was installed
  
  await browser.close();
}

testDapp().catch(console.error);

Making EIP-1193 Requests

The library sets up a local API server that handles EIP-1193 requests. In the browser context, you can use window.eip1193Request to make requests:

// In browser context
const accounts = await window.eip1193Request({
  method: "eth_accounts",
  params: []
});

const balance = await window.eip1193Request({
  method: "eth_getBalance",
  params: [accounts[0], "latest"]
});

API Reference

installMockWallet(options)

Installs a mock wallet in the Playwright page.

Options:

• page: Playwright Page object
• account: Viem LocalAccount object
• transports (optional): Record of chain ID to Transport mappings
• defaultChain (optional): Default chain to use
• debug (optional): Enable debug logging
• wallet (optional): Use a pre-configured wallet instance instead of creating a new one

eip1193Request Parameters

• method: The EIP-1193 method to call (e.g., "eth_accounts", "eth_getBalance")
• params: Array of parameters for the method
• uuid: Wallet UUID (automatically managed by the library)
• debug: Enable debug logging

Examples

Testing a Connect Wallet Button

import { test, expect } from "@playwright/test";
import { installMockWallet } from "@finn_gal/playwright-wallet-mock-ts";
import { privateKeyToAccount } from "viem/accounts";
import { mainnet } from "viem/chains";
import { http } from "viem";

test("connect wallet button works", async ({ page }) => {
  await installMockWallet({
    page,
    account: privateKeyToAccount(
      "0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80",
    ),
    defaultChain: mainnet,
    transports: { [mainnet.id]: http() },
    debug: true,
  });

  await page.goto("https://your-dapp-url.com");
  
  // Click the connect wallet button
  await page.getByRole("button", { name: "Connect Wallet" }).click();
  
  // Check if the wallet address is displayed
  await expect(page.getByText("0x71C7656EC7ab88b098defB751B7401B5f6d8976F")).toBeVisible();
});

License

ISC