惯性聚合 高效追踪和阅读你感兴趣的博客、新闻、科技资讯
阅读原文 在惯性聚合中打开

推荐订阅源

Blog — PlanetScale
Blog — PlanetScale
N
Netflix TechBlog - Medium
博客园 - 司徒正美
The GitHub Blog
The GitHub Blog
G
Google Developers Blog
Stack Overflow Blog
Stack Overflow Blog
博客园_首页
Google DeepMind News
Google DeepMind News
博客园 - 【当耐特】
freeCodeCamp Programming Tutorials: Python, JavaScript, Git & More
Recent Announcements
Recent Announcements
aimingoo的专栏
aimingoo的专栏
OSCHINA 社区最新新闻
OSCHINA 社区最新新闻
Y
Y Combinator Blog
B
Blog RSS Feed
人人都是产品经理
人人都是产品经理
MongoDB | Blog
MongoDB | Blog
量子位
博客园 - Franky
奇客Solidot–传递最新科技情报
奇客Solidot–传递最新科技情报
The Cloudflare Blog
有赞技术团队
有赞技术团队
Jina AI
Jina AI
GbyAI
GbyAI

DEV Community

Authentication Security Deep Dive: From Brute Force to Salted Hashing (With Java Examples) Why AI Systems Don’t Fail — They Drift Spilling beans for how i learn for exam😁"Reinforcement Learning Cheat Sheet" I Replaced Chrome with Safari for AI Browser Automation. Here's What Broke (and What Finally Worked) How Python Borrows Other People's Work The $40 Architecture: Processing 1 Billion API Requests with 99.99% Uptime Vibe Coding: A Workflow Guide (From Zero to SaaS) Most webhook security guides protect the wrong side. The scary part is delivery. Headless CMS for TanStack Start: Build a Blog with Cosmic EU Age Verification App "Hacked in 2 Minutes" — What Actually Happened Comfy Cloud’s delete function does not actually remove files Running AI Models on GPU Cloud Servers: A Beginner Guide Event-driven media intelligence with AWS Step Functions and Bedrock I scored 500 AI prompts across 8 quality dimensions — here's what broke How to Call Google Gemini API from Next.js (Free Tier, No Backend Needed) The Portal Protocol: Reclaiming Human Connection in the Age of AI How to Fix Your Team's Scattered Knowledge Problem With a Self-Hosted Forum Intro to tc Cloud Functors: A Graph-First Mental Model for the Modern Cloud Designing Multi-Tenant Backends With Both Ownership and Team Access I Built a Neumorphic CSS Library with 77+ Components — Here's What I Learned PostgreSQL Performance Optimization: Why Connection Pooling Is Critical at Scale Cómo construí un SaaS multi-rubro para gestionar expensas en Argentina con FastAPI + Vue 3 🚀 I Built an Ethical Hacking Scanner Tool – Open Source Project I Replaced /usage and /context in Claude Code With a Single Statusline A Pythonic Way to Handle Emails (IMAP/SMTP) with Auto-Discovery and AI-Ready Design I Collected 8.9 Million Polymarket Price Points — Here's What I Found About How Markets Really Move EcoTrack AI — Carbon Footprint Tracker & Dashboard Everyone's Using AI. No One Agrees How. 5 self-hosted ebook managers worth trying in 2026 Building Your First AI Agent with LangChain: From Chatbot to Autonomous Assistant
Cypress Testing: Complete Beginner's Guide
Yogesh Chavan · 2026-06-06 · via DEV Community

Section 1: Getting Started with Cypress

1. Installing and Setting Up Cypress

Prerequisites

Before installing Cypress, ensure you have Node.js installed on your machine. Cypress requires Node.js 18.x or 20.x and above. You should also have an existing React project or create a new one.

Check your Node.js version by running this command in your terminal:

node --version
# Should output v18.x.x or higher

Creating a React Project (Optional)

If you don't have an existing React project, create one using Vite which is the recommended approach for new React projects:

npm create vite@latest my-react-app -- --template react
cd my-react-app
npm install

Installing Cypress

Navigate to your React project directory and install Cypress as a development dependency. Cypress is a fairly large package, so the installation might take a minute or two:

npm install cypress --save-dev

# Or using yarn
yarn add cypress --dev

Opening Cypress for the First Time

After installation, open Cypress for the first time. This will create the initial folder structure and configuration files:

npx cypress open

When Cypress opens for the first time, you'll see a welcome screen where you can choose between E2E Testing and Component Testing. Select E2E Testing to get started with end-to-end tests.

Cypress will then prompt you to choose a browser. You can select Chrome, Firefox, Edge, or Electron. Choose your preferred browser and click Start E2E Testing in [Browser].

Adding NPM Scripts

Add convenient scripts to your package.json for running Cypress tests:

{
  "scripts": {
    "dev": "vite",
    "build": "vite build",
    "cy:open": "cypress open",
    "cy:run": "cypress run",
    "test:e2e": "start-server-and-test dev http://localhost:5173 cy:run"
  }
}

Tip: Use npm run cy:open for interactive development with the Cypress Test Runner. Use npm run cy:run for headless execution in CI/CD pipelines.


2. Understanding Cypress Project Structure

Project Directory Overview

After initializing Cypress, you'll notice several new folders and files in your project. Understanding each directory and file is essential for organizing your tests effectively.

my-react-app/
├── cypress/
│   ├── downloads/
│   ├── e2e/
│   │   └── spec.cy.js
│   ├── fixtures/
│   │   └── example.json
│   └── support/
│       ├── commands.js
│       └── e2e.js
├── cypress.config.js
├── package.json
└── src/
    └── (your React app)

Key Directories and Files

cypress/e2e/

This is where your test files live. Each test file should have the .cy.js extension (or .cy.ts for TypeScript). Cypress will automatically discover and run all test files in this directory.

cypress/fixtures/

Fixtures are used to store static test data, typically in JSON format. You can use fixtures to mock API responses or provide consistent test data across multiple tests.

// cypress/fixtures/user.json
{
  "name": "John Doe",
  "email": "john@example.com",
  "role": "admin"
}

cypress/support/commands.js

This file is where you define custom Cypress commands. Custom commands help you create reusable test logic that can be shared across multiple test files.

// cypress/support/commands.js

// Custom command to login
Cypress.Commands.add('login', (email, password) => {
  cy.visit('/login');
  cy.get('[data-testid="email"]').type(email);
  cy.get('[data-testid="password"]').type(password);
  cy.get('[data-testid="submit"]').click();
});

cypress.config.js

This is the main configuration file for Cypress. Here you can set the base URL, viewport dimensions, timeouts, and many other options.

// cypress.config.js
import { defineConfig } from 'cypress';

export default defineConfig({
  e2e: {
    baseUrl: 'http://localhost:5173',
    viewportWidth: 1280,
    viewportHeight: 720,
    defaultCommandTimeout: 10000,
    setupNodeEvents(on, config) {
      // implement node event listeners here
    },
  },
});

Tip: Always set a baseUrl in your cypress.config.js. This allows you to use cy.visit('/') instead of cy.visit('http://localhost:5173/'), making your tests cleaner and easier to maintain.

Configuring ESLint for Cypress

When you open Cypress test files in VS Code, you might see ESLint errors like the following:

// Error shown in VS Code:
// 'describe' is not defined. eslint(no-undef)
// 'it' is not defined. eslint(no-undef)
// 'cy' is not defined. eslint(no-undef)
// 'beforeEach' is not defined. eslint(no-undef)

This happens because ESLint doesn't know about Cypress global variables. These are not actual errors — your tests will still run. However, to fix these warnings and get proper IntelliSense support, install the Cypress ESLint plugin:

npm install eslint-plugin-cypress --save-dev

Then update your ESLint configuration file (eslint.config.js). First, add the import at the top of the file:

import cypressPlugin from 'eslint-plugin-cypress';

Then add the following configuration to your ESLint config:

plugins: {
  cypress: cypressPlugin,
},
extends: [
  js.configs.recommended,
  'plugin:cypress/recommended',
  reactHooks.configs.flat.recommended,
  reactRefresh.configs.vite,
],
env: {
  'cypress/globals': true,
},


3. Writing Your First Cypress Test

Test File Structure

Cypress uses Mocha's BDD syntax for structuring tests. If you've used Jest or Mocha before, you'll feel right at home. Tests are organized using describe blocks for grouping and it blocks for individual tests.

Let's create your first test file. First, here's the React component we'll be testing — a simple Home page component:

// src/pages/Home.jsx
import { Link } from 'react-router-dom';

const Home = () => {
  return (
    <div className="home">
      <h1>Welcome to Our App</h1>
      <p>This is the home page of our application.</p>
      <nav>
        <Link to="/about">About</Link>
        <Link to="/contact">Contact</Link>
        <Link to="/counter">Counter</Link>
      </nav>
    </div>
  );
};

export default Home;

Setting Up the App with Routing

To use this Home component, we need to set up React Router in our application. First, install react-router-dom:

npm install react-router-dom

Now, set up your App.jsx with routing to use the Home component:

// src/App.jsx
import { BrowserRouter, Routes, Route } from 'react-router-dom';
import Home from './pages/Home';

const App = () => {
  return (
    <BrowserRouter>
      <Routes>
        <Route path="/" element={<Home />} />
      </Routes>
    </BrowserRouter>
  );
};

export default App;

Start your development server to run the application:

npm run dev
# App will be available at http://localhost:5173

Writing the Test

Now, create a new file called home.cy.js in the cypress/e2e directory to test this component:

// cypress/e2e/home.cy.js

describe('Home Page', () => {
  beforeEach(() => {
    // Visit the home page before each test
    cy.visit('/');
  });

  it('should display the welcome message', () => {
    cy.contains('Welcome to Our App').should('be.visible');
  });

  it('should have a navigation menu', () => {
    cy.get('nav').should('exist');
    cy.get('nav a').should('have.length.at.least', 1);
  });
});

Code Explanation

  • cy.visit('/') — Navigates to the home page of your application. The '/' path uses the baseUrl configured in cypress.config.js.

  • cy.contains('Welcome to Our App') — Searches the DOM for an element containing the specified text.

  • .should('be.visible') — Asserts that the element is visible on the page. This checks that the element exists, is in the viewport, and is not hidden by CSS.

  • cy.get('nav') — Selects the nav element from the DOM.

  • .should('exist') — Asserts that the element exists in the DOM. Unlike 'be.visible', this doesn't check if the element is actually visible to the user.

  • .should('have.length.at.least', 1) — Asserts that there is at least one matching element (in this case, at least one link inside the nav).

Important: Make sure inside cypress.config.js file, you have set the baseUrl to http://localhost:5173 for this test to pass. This allows cy.visit('/') to navigate to your local development server.

When you run npm run cy:open and select E2E Testing, you'll see the Cypress Test Runner interface. It will display your test files under the cypress/e2e folder. You should see your home.cy.js file listed there. Click on it to run the tests.

Understanding the Test Structure

  • describe() — Groups related tests together. You can nest describe blocks for better organization. The first argument is a string describing what you're testing.

  • beforeEach() — Runs before each test in the describe block. Perfect for setup tasks like visiting a page or logging in. There's also afterEach(), before(), and after().

  • it() — Defines an individual test case. Each it block should test one specific behavior. The first argument describes what the test should do.

Want the Complete Guide?

This article is an excerpt from my Cypress Testing - Complete Beginner's Guide. For the full, in-depth walkthrough — with every concept explained step-by-step and ready-to-use code examples — check out the complete guide.

Here's everything you'll learn inside:

→ What is Cypress & why it's replacing Selenium for modern web testing
→ Installing and setting up Cypress from scratch
→ Writing your first Cypress test (step-by-step with a real React app)
→ Selecting elements the right way — so your tests never break randomly
→ Interacting with elements — clicks, typing, dropdowns, file uploads & more
→ Assertions and expectations that actually work (and auto-retry)
→ Working with aliases and handling Cypress's async behavior
→ Testing React components in complete isolation
→ Mocking API calls with cy.intercept() for fast, reliable tests
→ Testing forms, validation, and real-time user input
→ Testing authentication flows — login, logout & protected routes
→ Best practices used by top engineering teams to keep test suites maintainable

If you found this article helpful, the full guide takes it much further.

Want More Such Guides? Check out the Ultimate React Ebooks Collection with 20+ useful and practical guides.


Don't Miss This!

Don't miss the Lifetime/Pro Subscription — get lifetime access to all my 30+ current and all future courses, ebooks, webinars along with Applications Source Code Bundle (Bonus Offer), for just $10 / ₹850 (95% OFF).

Limited-Time Offer
One-Time Payment
Lifetime Access
All Future Courses/ebooks/webinars Included

The discount won't stay forever. Grab it while it's available.

About Me

I'm a freelancer, mentor, and full-stack developer with 12+ years of experience, working primarily with React, Next.js, and Node.js.

Alongside building real-world web applications, I'm also an Industry/Corporate Trainer, training developers and teams in modern JavaScript, Next.js, and MERN stack technologies with a focus on practical, production-ready skills.

I've also created various courses with 3000+ students enrolled.

My Portfolio: https://yogeshchavan.dev/

Follow me on LinkedIn for regular content that I share every day.