API Testing Tutorial

Learn how to master the Dual API Strategy in TAFLEX JS. Choose the right tool for the right job: Playwright for integrated flows or Axios for high-performance specialized tests.

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1. Hybrid Approach (Playwright)

Use case: Integrated tests where you need to share authentication with a browser or see API calls in a Trace Viewer.

Creating the Test

Create a standard Playwright spec in tests/api/:

import { test, expect } from '../fixtures.ts';

test.describe('Hybrid API Strategy (Playwright)', () => {
    // 1. Configure mode
    test.use({ mode: 'api' });

    test('should validate user profile integration', async ({ driver }) => {
        // 2. Perform request
        const response = await driver.get('/users/1');
        
        // 3. Assert using Playwright matchers
        expect(response.status()).toBe(200);
        const user = await response.json();
        expect(user.username).toBe('Bret');
    });
});

How to run:

npx playwright test tests/api/

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2. Specialized Approach (Axios + Vitest)

Use case: Standalone API testing, contract validation, and extreme execution speed.

Creating the Test

Create a file ending in .axios.spec.ts in tests/api/. These tests use Vitest as the runner.

import { describe, it, expect, beforeAll } from 'vitest';
import { DriverFactory } from '../../src/core/drivers/driver.factory.ts';

describe('Specialized API Strategy (Axios + Vitest)', () => {
    let driver;

    beforeAll(async () => {
        // 1. Initialize driver with api mode
        // Ensure API_PROVIDER=axios is set in .env
        driver = DriverFactory.create('api'); 
        await driver.initialize({
            apiBaseUrl: 'https:/.jsonplaceholder.typicode.com'
        });
    });

    it('should validate user contract with high performance', async () => {
        // 2. Perform request
        const response = await driver.get('/users/1');
        
        // 3. Standard Vitest assertions
        expect(response.status()).toBe(200);
        const user = await response.json();
        expect(user.id).toBe(1);
    });
});

How to run:

# Set provider if not default in .env
API_PROVIDER=axios npm run test:unit

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3. Which one should I choose?

Feature	Playwright Strategy	Axios Strategy
Runner	Playwright	Vitest
Speed	Moderate	Fast (Blazing)
Trace Viewer	Yes	No
Authentication Sharing	Native with Browser	Manual
Watch Mode	npx playwright test --ui	npm run test:unit (Auto-watch)

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4. Best Practices

• Shared Locators: Use src/resources/locators/api/common.json to store endpoints for both strategies.
• Environment URLs: Always rely on API_BASE_URL in your .env.
• Validation: For both strategies, the driver wrapper provides consistent status(), .json(), and ok()` methods to keep your code portable.