End-to-end (E2E) testing is a crucial part of the software development lifecycle, ensuring that the entire application flow works as expected from start to finish. In this section, we will explore how to perform E2E testing using Playwright with TypeScript.
Key Concepts of End-to-End Testing
- User Journey Simulation: E2E tests simulate real user scenarios to verify that the application behaves correctly.
- Full System Testing: These tests cover the entire application stack, including the frontend, backend, and any integrated services.
- Environment Setup: E2E tests often require a specific environment setup that mirrors production as closely as possible.
Setting Up Playwright for E2E Testing
Before writing E2E tests, ensure that Playwright is installed and configured in your project. If you haven't set up Playwright yet, refer to Module 2 for installation instructions.
Example: Basic E2E Test
Let's create a simple E2E test to verify the login functionality of a web application.
import { chromium, Browser, Page } from 'playwright';
(async () => {
const browser: Browser = await chromium.launch();
const page: Page = await browser.newPage();
// Navigate to the login page
await page.goto('https://example.com/login');
// Fill in the login form
await page.fill('#username', 'testuser');
await page.fill('#password', 'password123');
// Submit the form
await page.click('button[type="submit"]');
// Verify successful login by checking the URL or a specific element
await page.waitForSelector('#welcome-message');
const welcomeMessage = await page.textContent('#welcome-message');
console.log(welcomeMessage); // Should print a welcome message
await browser.close();
})();Explanation
- Browser and Page: We launch a Chromium browser instance and create a new page.
- Navigation: The script navigates to the login page of the application.
- Form Interaction: We fill in the username and password fields and submit the form.
- Verification: After submission, we wait for a specific element that indicates a successful login and print its content.
Practical Exercise
Exercise: Write an E2E test to verify the search functionality on a website.
- Navigate to the homepage of a website with a search feature.
- Enter a search query in the search input field.
- Submit the search form.
- Verify that the search results page displays results related to the query.
Solution:
import { chromium, Browser, Page } from 'playwright';
(async () => {
const browser: Browser = await chromium.launch();
const page: Page = await browser.newPage();
// Navigate to the homepage
await page.goto('https://example.com');
// Enter a search query
await page.fill('#search-input', 'Playwright');
// Submit the search form
await page.click('button[type="submit"]');
// Verify search results
await page.waitForSelector('.search-results');
const results = await page.$$eval('.search-result-item', items => items.map(item => item.textContent));
console.log(results); // Should print an array of search result titles
await browser.close();
})();Common Mistakes and Tips
- Element Selectors: Ensure that the selectors used in your tests are accurate and stable. Use data attributes or unique IDs when possible.
- Timing Issues: Use
waitForSelectoror similar methods to handle asynchronous operations and ensure elements are available before interacting with them. - Environment Consistency: Run tests in an environment that closely resembles production to catch environment-specific issues.
Conclusion
End-to-end testing with Playwright allows you to automate complex user interactions and verify the complete functionality of your application. By simulating real user scenarios, you can ensure that your application behaves as expected in production. In the next section, we will explore visual testing with Playwright, which complements E2E testing by verifying the visual aspects of your application.
Playwright with TypeScript: From Beginner to Advanced
Module 1: Introduction to Playwright and TypeScript
- What is Playwright?
- Setting Up Your Development Environment
- Introduction to TypeScript
- Basic TypeScript Syntax
Module 2: Getting Started with Playwright
- Installing Playwright
- Creating Your First Playwright Script
- Understanding Playwright's Core Concepts
- Running Playwright Tests
Module 3: Playwright and TypeScript Basics
- Writing Tests in TypeScript
- Using TypeScript Interfaces and Types
- Debugging Playwright Tests
- Handling Asynchronous Code
Module 4: Advanced Playwright Features
- Working with Selectors
- Handling Multiple Pages and Frames
- Network Interception and Mocking
- Emulating Devices and Geolocation
Module 5: Test Automation Strategies
- Organizing Tests and Test Suites
- Using Fixtures and Hooks
- Parallel Test Execution
- Continuous Integration with Playwright
Module 6: Advanced TypeScript Techniques
- Generics in TypeScript
- Advanced TypeScript Types
- TypeScript Decorators
- TypeScript and Playwright Best Practices
Module 7: Real-World Playwright Applications
- End-to-End Testing with Playwright
- Visual Testing with Playwright
- Performance Testing with Playwright
- Case Study: Implementing Playwright in a Project