Test Smart Contracts

In this section, you'll set up a smart contract test and test your contract using Mocha and Chai testing frameworks. See DApps Automation using Cucumber and Playwright.

Follow these steps below to test the smart contract.

Step 1: Install Dependencies

We'll install the Mocha and Chai testing dependencies.

Mocha is a JavaScript test framework running on Node.js. Chai is an assertion library for the browser and Node that can be paired with any JavaScript testing framework.

• Before writing tests for your token contract, ensure Mocha and Chai is installed. To install the required testing dependencies:

  npm install --save-dev mocha@10.2.0 chai@4.2.0 @nomiclabs/hardhat-ethers@2.2.3

Step 2: Create Tests

1. Navigate to the test directory in the root directory of your project, this is recommended for storing all test files:

  cd test

2. In the test directory, open the MyToken.test.js file, we'll write tests for the token contract using Mocha and Chai:

Copy the code snippet below and paste it in your test file or see the MyToken.test.js file on GitHub.

  const { expect } = require("chai");
  const { ethers } = require("hardhat");

  describe("MyToken", function () {
  it("Should deploy MyToken and assign the total supply to the owner", async function () {
    const [owner] = await ethers.getSigners();

    const MyToken = await ethers.getContractFactory("MyToken");
    const myToken = await MyToken.deploy(1000);
    await myToken.deployed();

    expect((await myToken.totalSupply()).toString()).to.equal('1000');
    expect((await myToken.balanceOf(owner.address)).toString()).to.equal('1000');
      });
  });

Step 3: Run the Tests

To execute tests, run the following command in your project's root directory. This will run the written tests, confirming that the contract works as expected.

npx hardhat test

You should get a response like below:

By following these steps, you'll have the necessary testing frameworks installed and be well prepared to write effective tests for your smart contract.

Alternative Testing Approaches and Frameworks

In addition to Mocha and Chai, you can use several other frameworks and approaches in your Hardhat project. Each has its unique features and benefits.

• Jest - JavaScript Testing Framework
  • Jest is popular for its delightful syntax and focus on simplicity. It works well for testing both frontend and backend JavaScript applications.
• Waffle - Ethereum Smart Contract Testing Library
  • Waffle is a library for writing and testing smart contracts. It is often used with ethers.js and is known for its fluent syntax.
• Cucumber DApps Automation
  • dApp Automation with Cucumber