Replay AI: Automating UI Testing with Video-Based Code Generation

TL;DR: Replay AI drastically reduces UI testing time and effort by automatically generating testable code from screen recordings, leveraging behavior-driven reconstruction for accurate and reliable results.

The promise of automated UI testing has always been tantalizing, yet consistently falls short. Screenshot-to-code tools offer a superficial solution, capturing only the visual representation of an interface. They miss the crucial element: user intent. You're left with code that looks right but fails to truly behave correctly under real-world conditions. This is where behavior-driven reconstruction, powered by Replay AI, changes the game.

The Problem with Traditional UI Testing#

Traditional UI testing is a time sink. Manually writing tests is tedious, error-prone, and requires constant maintenance as the UI evolves. Automation tools, while helpful, often rely on brittle selectors and fragile assertions that break with minor UI changes. The result? A testing bottleneck that slows down development and increases the risk of shipping bugs.

Furthermore, traditional testing often focuses on individual components in isolation. It struggles to capture the complex interactions and workflows that users actually experience. This leads to a false sense of security, where individual components pass tests but the overall user experience is broken.

Introducing Behavior-Driven Reconstruction with Replay AI#

Replay AI takes a fundamentally different approach. Instead of relying on static screenshots or brittle selectors, Replay AI analyzes video recordings of user interactions. This allows it to understand the behavior of the user, not just the visual appearance of the UI. Using Gemini, Replay reconstructs the UI and generates working code based on this behavior. This "behavior-driven reconstruction" is the key to unlocking truly automated UI testing.

Replay understands:

• •User clicks and gestures
• •Data input and form submissions
• •Navigation between pages
• •Dynamic UI updates

This holistic understanding allows Replay to generate more accurate, reliable, and maintainable tests.

How Replay Works: A Step-by-Step Guide#

Here's how you can use Replay to automate your UI testing:

Step 1: Record User Flows#

Record videos of users interacting with your application. These videos should capture the key user flows you want to test. Tools like Loom, or even built-in screen recording features on operating systems, can be used.

💡 Pro Tip: Focus on recording realistic user scenarios, including edge cases and error conditions. The more comprehensive your recordings, the better the generated code will be.

Step 2: Upload to Replay#

Upload the video recordings to Replay. Replay will then analyze the videos and reconstruct the UI.

Step 3: Generate Code#

Replay will generate working code based on the behavior observed in the videos. This code can be in a variety of languages and frameworks, including React, Vue, and Angular.

typescript
// Example generated React component
import React, { useState } from 'react';

const GeneratedComponent = () => {
  const [text, setText] = useState('');

  const handleChange = (event: React.ChangeEvent<HTMLInputElement>) => {
    setText(event.target.value);
  };

  const handleSubmit = (event: React.FormEvent) => {
    event.preventDefault();
    alert(`Submitted: ${text}`);
  };

  return (
    <form onSubmit={handleSubmit}>
      <input type="text" value={text} onChange={handleChange} />
      <button type="submit">Submit</button>
    </form>
  );
};

export default GeneratedComponent;

Step 4: Integrate with Your Testing Framework#

Integrate the generated code with your existing testing framework. This allows you to run the generated tests as part of your CI/CD pipeline.

Step 5: Customize and Refine#

While Replay generates working code, you may need to customize and refine it to meet your specific needs. This is where your expertise as a developer comes in.

📝 Note: Replay is not a replacement for human developers. It's a tool to augment your capabilities and accelerate your development process.

Replay Features: Powering Automated UI Testing#

Replay offers a range of features that make it a powerful tool for automating UI testing:

• •Multi-page generation: Replay can generate code for multi-page applications, capturing the flow of users between different pages.
• •Supabase integration: Replay seamlessly integrates with Supabase, allowing you to easily store and manage your UI data.
• •Style injection: Replay can inject styles into the generated code, ensuring that the UI looks as intended.
• •Product Flow maps: Replay generates visual maps of user flows, making it easier to understand and debug complex interactions.

Replay vs. Traditional Screenshot-to-Code Tools#

The table below highlights the key differences between Replay and traditional screenshot-to-code tools:

⚠️ Warning: Screenshot-to-code tools often struggle with dynamic UI elements and complex interactions. Replay's video-based approach provides a much more robust solution.

Automating UI Testing: A Concrete Example#

Imagine you need to test a simple e-commerce checkout flow. A user adds an item to their cart, proceeds to checkout, enters their shipping information, and submits their order.

With traditional UI testing, you would need to write numerous tests to cover each step of this flow. These tests would need to interact with various UI elements, such as buttons, input fields, and dropdown menus.

With Replay, you can simply record a video of a user completing this flow. Replay will then analyze the video and generate code that replicates the user's actions. This generated code can be easily integrated with your testing framework, allowing you to automatically test the entire checkout flow.

javascript
// Example generated test using Jest and React Testing Library
import { render, screen, fireEvent } from '@testing-library/react';
import GeneratedComponent from './GeneratedComponent'; // Replay generated component

describe('Checkout Flow', () => {
  it('should successfully complete the checkout flow', () => {
    render(<GeneratedComponent />);

    // Simulate adding an item to the cart
    const addToCartButton = screen.getByText('Add to Cart');
    fireEvent.click(addToCartButton);

    // Simulate proceeding to checkout
    const checkoutButton = screen.getByText('Checkout');
    fireEvent.click(checkoutButton);

    // Simulate entering shipping information
    const nameInput = screen.getByLabelText('Name');
    fireEvent.change(nameInput, { target: { value: 'John Doe' } });

    const addressInput = screen.getByLabelText('Address');
    fireEvent.change(addressInput, { target: { value: '123 Main St' } });

    // Simulate submitting the order
    const submitButton = screen.getByText('Submit Order');
    fireEvent.click(submitButton);

    // Assert that the order was successfully submitted
    expect(screen.getByText('Order Confirmation')).toBeInTheDocument();
  });
});

Benefits of Using Replay for UI Testing#

• •Reduced Testing Time: Automate the creation of UI tests, freeing up developers to focus on other tasks.
• •Improved Test Coverage: Capture complex user flows and edge cases that are often missed by manual testing.
• •Increased Test Reliability: Generate tests that are less brittle and more resistant to UI changes.
• •Faster Development Cycles: Accelerate the development process by identifying and fixing bugs earlier in the cycle.
• •Better User Experience: Ensure that your application provides a smooth and intuitive user experience.

Frequently Asked Questions#

Is Replay free to use?#

Replay offers a free tier with limited features, as well as paid plans for more advanced functionality and usage. Check the pricing page for the most up-to-date information.

How is Replay different from v0.dev?#

While both tools aim to generate code, Replay focuses specifically on reconstructing UIs from video recordings, enabling behavior-driven generation and comprehensive testing. v0.dev, while powerful for initial UI creation, doesn't inherently understand user behavior in the same way. Replay can also integrate with existing codebases, augmenting rather than replacing them.

What types of applications can Replay be used with?#

Replay can be used with a wide range of web applications, including single-page applications, multi-page applications, and progressive web apps.

What programming languages and frameworks does Replay support?#

Replay supports a variety of popular programming languages and frameworks, including React, Vue, Angular, and more.

---

Ready to try behavior-driven code generation? Get started with Replay - transform any video into working code in seconds.