Mocking HTTPX Requests with RESPX: A Comprehensive Guide

Mocking HTTP requests is essential for testing APIs without making real network calls. RESPX is a powerful library that allows developers to mock HTTPX requests efficiently, including handling headers, query parameters, and response payloads. Learn how to mock HTTPX requests with RESPX.

Why Mock HTTPX Requests?

✅ Faster Testing – Avoids delays caused by actual network calls. ✅ More Reliable Tests – Eliminates dependency on external APIs. ✅ Better Control – Simulates different API responses and error handling. ✅ Reduces Costs – Avoids unnecessary API calls that may incur charges.

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Installing RESPX

To get started with RESPX, install it using pip:

pip install respx

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Mocking HTTPX Requests with RESPX

1. Basic Mocking

import httpx
import respx

# Create a mock response
respx.get("https://api.example.com/data").mock(return_value=httpx.Response(200, json={"message": "Success"}))

# Make the actual request
response = httpx.get("https://api.example.com/data")
print(response.json())  # Output: {'message': 'Success'}

2. Mocking Requests with Headers

Mock responses with custom headers:

respx.get("https://api.example.com/data").mock(
    return_value=httpx.Response(200, json={"message": "Success"}, headers={"X-Custom-Header": "Mocked"})
)

response = httpx.get("https://api.example.com/data")
print(response.headers["X-Custom-Header"])  # Output: Mocked

3. Mocking Requests with Query Parameters

respx.get("https://api.example.com/data", params={"id": "123"}).mock(return_value=httpx.Response(200, json={"id": 123, "name": "Test"}))

response = httpx.get("https://api.example.com/data", params={"id": "123"})
print(response.json())  # Output: {'id': 123, 'name': 'Test'}

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Best Practices for Mocking HTTPX Requests

✅ Use Clear and Specific Routes – Avoid over-mocking with generic URLs. ✅ Test Multiple Response Scenarios – Mock success, failures, and timeouts. ✅ Ensure Headers and Query Params Are Handled – Keep responses realistic. ✅ Integrate with CI/CD – Automate API testing in your pipeline. ✅ Use Keploy for AI-Powered API Mocking – Generate mocks directly from real-world traffic.

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Integrating RESPX with Keploy

Keploy automates API mocking by recording real API interactions and converting them into reusable mocks. By combining Keploy and RESPX, developers can streamline their API testing workflow and reduce manual effort. Learn more about Keploy's API automation.

Conclusion

Mocking HTTPX requests with RESPX is an effective way to improve API testing efficiency and reliability. By properly handling headers, query parameters, and responses, developers can create robust test cases. Keploy further enhances this process by automating test generation. Explore RESPX for API mocking.