Python API Testing Examples Using requests, unittest, pytest, and jsonschema

Example 1: GET request using requests

import requests
response = requests.get('https://api.example.com/data')
print(response.status_code)
print(response.json())

Output example:

200
{'status': 'success', 'data': {...}}

Example 2: POST request using requests

import requests
import json
payload = {'key1': 'value1', 'key2': 'value2'}
headers = {'content-type': 'application/json'}
response = requests.post('https://api.example.com/endpoint', data=json.dumps(payload), headers=headers)
print(response.status_code)
print(response.text)

Output example:

201
{"message": "Resource created"}

Example 3: HTTP authentication with requests

import requests
response = requests.get('https://api.example.com/protected', auth=('username', 'password'))
print(response.status_code)
print(response.json())

Output example:

200
{'message': 'Access granted'}

Example 4: File upload with requests

import requests
files = {'file': open('example.txt', 'rb')}
response = requests.post('https://api.example.com/upload', files=files)
print(response.status_code)
print(response.text)

Output example:

200
{"filename": "example.txt"}

Example 5: Handling redirects with requests

import requests
response = requests.get('http://redirect.example.com', allow_redirects=True)
print(response.url)
print(response.status_code)

Output example:

https://final.example.com
200

Example 6: Unit test with unittest framework

import unittest
import requests
class TestAPI(unittest.TestCase):
    def test_get_request(self):
        response = requests.get('https://api.example.com/data')
        self.assertEqual(response.status_code, 200)

if __name__ == '__main__':
    unittest.main()

Output example:

..
----------------------------------------------------------------------
Ran 1 test in 0.001s
OK

Example 7: Test case with pytest

import requests
import pytest
def test_post_request():
    payload = {'key1': 'value1'}
    response = requests.post('https://api.example.com/endpoint', data=payload)
    assert response.status_code == 201

Run test: pytest -v test_api.py

Output example:

test_api.py::test_post_request PASSED

Example 8: Mocking HTTP responses with responses library

import responses
import requests
@responses.activate
def test_mock_response():
    responses.add(responses.GET, 'https://api.example.com/data', json={'status': 'ok'}, status=200)
    response = requests.get('https://api.example.com/data')
    assert response.json()['status'] == 'ok'

Output example: (no direct output, assertion passes)

Example 9: Combining pytest with responses

import pytest
import responses
import requests
@responses.activate
def test_mocked_endpoint():
    responses.add(responses.POST, 'https://api.example.com/endpoint', json={'message': 'Mocked'}, status=200)
    response = requests.post('https://api.example.com/endpoint')
    assert response.json()['message'] == 'Mocked'

Run test: pytest -v test_api.py

Output example:

test_api.py::test_mocked_endpoint PASSED

Example 10: Validating response structure with jsonschema

import requests
import jsonschema
schema = {
    "type": "object",
    "properties": {
        "status": {"type": "string"},
        "data": {"type": "object"}
    },
    "required": ["status", "data"]
}

def validate_response(response):
    try:
        jsonschema.validate(instance=response.json(), schema=schema)
        print("Response is valid.")
    except jsonschema.exceptions.ValidationError as err:
        print("Invalid response:", err)

validate_response(requests.get('https://api.example.com/data'))

Output example:

Response is valid.

These examples illustrate how to use Python for a variety of API automation testing tasks, from simple GET/POST requests to authentication, file uploads, redirects, unit testing, response mocking, and schema validation, providing practical guidance for backend testing workflows.