Streamlining Authentication Flow Testing with TypeScript and Open Source Tools

Source: Dev.to

Why Automate Authentication Flows?

Authentication systems are critical security components, and manual testing can be error‑prone and inefficient. Automated tests help catch regressions early, verify multiple scenarios, and simulate real‑world user behaviors efficiently. Automating these flows ensures your system adheres to security policies while maintaining a seamless user experience.

Choosing the Right Tools

For TypeScript‑based automation, the following open source tools and libraries form a robust stack:

• Playwright – Facilitates cross‑browser testing with a simple API.
• Auth0 or OIDC‑client – For handling OAuth/OpenID Connect flows.
• ts-node – Executes TypeScript scripts seamlessly.
• Jest – Provides a test runner and assertion framework.

Implementation Overview

Setting Up the Environment

Initialize a new Node.js project and install dependencies:

npm init -y
npm install playwright @openid/appauth jest ts-node typescript --save-dev

Create a tsconfig.json for TypeScript configuration:

{
  "compilerOptions": {
    "target": "ES6",
    "module": "commonjs",
    "strict": true,
    "esModuleInterop": true
  }
}

Add the following scripts to your package.json:

{
  "scripts": {
    "test": "jest",
    "start": "ts-node authFlowTest.ts"
  }
}

Writing Authentication Flow Tests

Create a file authFlowTest.ts:

import { chromium, Browser, Page } from 'playwright';

async function testAuthFlow() {
  const browser: Browser = await chromium.launch({ headless: true });
  const page: Page = await browser.newPage();
  try {
    // Navigate to your app's login page
    await page.goto('https://yourapp.com/login');

    // Fill in login credentials
    await page.fill('#username', 'testuser');
    await page.fill('#password', 'Password123');
    await Promise.all([
      page.click('#loginButton'),
      page.waitForNavigation(),
    ]);

    // Handle OAuth redirection if applicable
    const url = page.url();
    if (url.includes('oauth')) {
      // simulate OAuth flow, such as clicking authorize
      await page.click('#authorize');
      await page.waitForNavigation();
    }

    // Verify successful login
    const userProfile = await page.$('.user-profile');
    if (userProfile) {
      console.log('Authentication flow succeeded. User profile visible.');
    } else {
      throw new Error('Authentication failed: User profile not found.');
    }
  } catch (error) {
    console.error('Test failed:', error);
  } finally {
    await browser.close();
  }
}

testAuthFlow();

Running the Tests

Execute the script with:

npm start

Or run the full suite with Jest:

npm test

Additional Considerations

• Token Management – Validate OAuth tokens or session cookies post‑login.
• Error Scenarios – Automate invalid credentials, expired tokens, and permission errors.
• Multi‑Platform Testing – Extend tests with Playwright’s cross‑browser support.

Conclusion

By combining TypeScript with open source tools like Playwright, Jest, and OAuth libraries, QA teams can develop efficient, reliable automated authentication flow tests. This approach enhances test coverage and aligns with modern DevOps practices for continuous integration and delivery.

Investing in such automation strategies leads to improved security assurance, faster release cycles, and higher‑quality software products.

🛠️ QA Tip

To test safely without using real user data, you can use TempoMail USA.