Using pytest fixtures for API automation testing in Python

1. Login authentication Token management

import pytest
import requests

@pytest.fixture(scope="module")
def login_token():
    # 登录获取Token的逻辑
    login_data = {"username": "testuser", "password": "testpass"}
    response = requests.post("https://api.example.com/auth/login", json=login_data)
    token = response.json()["token"]
    yield token
    # 清理逻辑，例如登出操作
    logout_url = "https://api.example.com/auth/logout"
    requests.post(logout_url, headers={"Authorization": f"Bearer {token}"})

def test_protected_endpoint(login_token):
    headers = {"Authorization": f"Bearer {login_token}"}
    response = requests.get("https://api.example.com/protected-endpoint", headers=headers)
    assert response.status_code == 200

2. Database connection and teardown

import sqlite3
import pytest

@pytest.fixture(scope="function")
def db_connection():
    conn = sqlite3.connect(":memory:")
    yield conn
    conn.close()

def test_db_insert(db_connection):
    cursor = db_connection.cursor()
    cursor.execute("CREATE TABLE test (id INTEGER PRIMARY KEY, value TEXT)")
    cursor.execute("INSERT INTO test VALUES (1, 'example')")
    cursor.execute("SELECT * FROM test")
    rows = cursor.fetchall()
    assert rows == [(1, 'example')]

3. Temporary directory handling

import pytest
import os
import tempfile

@pytest.fixture(scope="function")
def temp_directory():
    with tempfile.TemporaryDirectory() as dir_path:
        yield dir_path

def test_write_and_read(temp_directory):
    with open(os.path.join(temp_directory, "test.txt"), "w") as file:
        file.write("Hello, World!")
    with open(os.path.join(temp_directory, "test.txt")) as file:
        content = file.read()
    assert content == "Hello, World!"

4. API client initialization and teardown

import requests
import pytest

@pytest.fixture(scope="session")
def api_client():
    client = requests.Session()
    yield client
    client.close()

def test_api_get(api_client):
    response = api_client.get("https://api.example.com/data")
    assert response.status_code == 200

5. Environment variable setup and restoration

import os
import pytest

@pytest.fixture(scope="function")
def set_env_variable():
    original_value = os.environ.get("SPECIAL_VAR", None)
    os.environ["SPECIAL_VAR"] = "test_value"
    yield
    if original_value is None:
        del os.environ["SPECIAL_VAR"]
    else:
        os.environ["SPECIAL_VAR"] = original_value

def test_env_var(set_env_variable):
    assert os.environ["SPECIAL_VAR"] == "test_value"

6. Service start and stop

import subprocess
import pytest

@pytest.fixture(scope="session")
def start_service():
    process = subprocess.Popen(["your-service-start-command"])
    yield
    process.terminate()
    process.wait(timeout=5)

def test_service_working(start_service):
    # Here you would add assertions to verify the service is running correctly
    pass

7. Configuration file loading and cleanup

import yaml
import pytest

@pytest.fixture(scope="function")
def load_config():
    with open("config.yaml", "r") as file:
        config = yaml.safe_load(file)
    yield config
    # If configuration changes need to be rolled back, handle it here

def test_config(load_config):
    assert load_config["database"]["host"] == "localhost"

8. Cache management

import cachetools
import pytest

@pytest.fixture(scope="session")
def cache():
    cache = cachetools.LRUCache(maxsize=100)
    yield cache
    cache.clear()

def test_cache(cache):
    cache["key"] = "value"
    assert cache["key"] == "value"

9. User role simulation

@pytest.fixture(params=["admin", "user", "guest"])
def user_role(request):
    return request.param

def test_access_rights(user_role):
    # Simulate permission checks based on role
    pass

10. HTTP header management

import pytest
import requests

@pytest.fixture
def custom_headers():
    headers = {"X-Custom-Header": "Value"}
    return headers

def test_with_custom_headers(custom_headers):
    response = requests.get("https://api.example.com", headers=custom_headers)
    assert response.status_code == 200

Each example shows how to define a pytest fixture to initialize a resource and then use that fixture in test functions; adjust URLs, database strings, and other configurations as needed for your specific environment and ensure required libraries (requests, pytest, cachetools, etc.) are installed.