API Testing Tutorial

Learn how to master the Dual API Strategy in TAFLEX PY. Choose the right tool for the right job: Playwright for integrated flows or HTTPX 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 pytest

@pytest.mark.api
def test_hybrid_api_strategy(api_driver):
    # Perform request
    response = api_driver.get('/users/1')
    
    # Assert
    assert response.status == 200
    user = response.json()
    assert user['username'] == 'Bret'

How to run:

pytest tests/api/

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2. Specialized Approach (HTTPX + Pytest)

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

Creating the Test

Create a file ending in test_*.py in tests/api/. These tests use Pytest as the runner.

import pytest
from src.core.drivers.driver_factory import DriverFactory

@pytest.fixture(scope="module")
def httpx_driver():
    # Ensure API_PROVIDER=httpx is set in .env
    driver = DriverFactory.create('api') 
    await driver.initialize({
        api_base_url: 'https://jsonplaceholder.typicode.com'
    })
    yield driver
    driver.terminate()

def test_specialized_api_strategy(httpx_driver):
    # 2. Perform request
    response = httpx_driver.get('/users/1')

    # 3. Standard Pytest assertions
    assert response.status_code == 200
    user = response.json()
    assert user['id'] == 1

How to run:

# Set provider if not default in .env
API_PROVIDER=httpx pytest tests/api/

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3. Which one should I choose?

Feature	Playwright Strategy	HTTPX Strategy
Runner	Playwright	Pytest
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.