Python自动化测试完整教程：pytest + selenium实战

# 使用webdriver-manager自动管理驱动
from webdriver_manager.chrome import ChromeDriverManager
from selenium import webdriver
from selenium.webdriver.chrome.service import Service

def setup_driver():
    service = Service(ChromeDriverManager().install())
    driver = webdriver.Chrome(service=service)
    return driver

项目结构搭建

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automation_project/
├── tests/
│   ├── __init__.py
│   ├── test_login.py
│   └── test_search.py
├── pages/
│   ├── __init__.py
│   ├── base_page.py
│   └── login_page.py
├── utils/
│   ├── __init__.py
│   └── config.py
├── drivers/
├── reports/
├── conftest.py
├── pytest.ini
└── requirements.txt

pytest基础教程

pytest核心概念

pytest是Python中最流行的测试框架，具有以下特点：

简单易用的断言语法
丰富的插件生态系统
强大的fixture机制
灵活的测试发现和执行

基础测试示例

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# test_basic.py
import pytest

def test_simple_assert():
    """基础断言测试"""
    assert 1 + 1 == 2

def test_string_operations():
    """字符串操作测试"""
    text = "Hello, World!"
    assert "Hello" in text
    assert text.startswith("Hello")
    assert text.endswith("!")

class TestCalculator:
    """测试类示例"""
    
    def test_addition(self):
        assert 2 + 3 == 5
    
    def test_division(self):
        assert 10 / 2 == 5
    
    def test_division_by_zero(self):
        with pytest.raises(ZeroDivisionError):
            10 / 0

fixture机制深入

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# conftest.py
import pytest
from selenium import webdriver
from webdriver_manager.chrome import ChromeDriverManager

@pytest.fixture(scope="session")
def driver():
    """会话级别的浏览器驱动"""
    options = webdriver.ChromeOptions()
    options.add_argument("--headless")  # 无头模式
    driver = webdriver.Chrome(
        service=Service(ChromeDriverManager().install()),
        options=options
    )
    yield driver
    driver.quit()

@pytest.fixture
def test_data():
    """测试数据fixture"""
    return {
        "username": "test@example.com",
        "password": "password123"
    }

参数化测试

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# test_parametrize.py
import pytest

@pytest.mark.parametrize("a,b,expected", [
    (2, 3, 5),
    (1, 1, 2),
    (0, 5, 5),
    (-1, 1, 0)
])
def test_addition(a, b, expected):
    assert a + b == expected

@pytest.mark.parametrize("url", [
    "https://www.baidu.com",
    "https://www.google.com"
])
def test_website_accessibility(driver, url):
    driver.get(url)
    assert driver.title

selenium基础教程

元素定位策略

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from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

class ElementLocator:
    """元素定位封装类"""
    
    def __init__(self, driver):
        self.driver = driver
        self.wait = WebDriverWait(driver, 10)
    
    def find_element_safely(self, locator):
        """安全查找元素"""
        try:
            element = self.wait.until(EC.presence_of_element_located(locator))
            return element
        except TimeoutException:
            print(f"元素定位失败: {locator}")
            return None
    
    def click_element(self, locator):
        """点击元素"""
        element = self.wait.until(EC.element_to_be_clickable(locator))
        element.click()
    
    def input_text(self, locator, text):
        """输入文本"""
        element = self.find_element_safely(locator)
        if element:
            element.clear()
            element.send_keys(text)

常用操作封装

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# utils/selenium_helper.py
from selenium.webdriver.support.ui import Select
from selenium.webdriver.common.action_chains import ActionChains
from selenium.webdriver.common.keys import Keys

class SeleniumHelper:
    """Selenium操作助手类"""
    
    def __init__(self, driver):
        self.driver = driver
    
    def scroll_to_element(self, element):
        """滚动到指定元素"""
        self.driver.execute_script("arguments[0].scrollIntoView();", element)
    
    def select_dropdown_by_text(self, locator, text):
        """通过文本选择下拉框"""
        select = Select(self.driver.find_element(*locator))
        select.select_by_visible_text(text)
    
    def hover_element(self, element):
        """鼠标悬停"""
        actions = ActionChains(self.driver)
        actions.move_to_element(element).perform()
    
    def switch_to_iframe(self, iframe_locator):
        """切换到iframe"""
        iframe = self.driver.find_element(*iframe_locator)
        self.driver.switch_to.frame(iframe)
    
    def take_screenshot(self, filename):
        """截图"""
        self.driver.save_screenshot(f"screenshots/{filename}")

pytest + selenium实战项目

实战项目：电商网站测试

让我们以一个电商网站为例，构建完整的自动化测试项目。

配置文件设置

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# utils/config.py
class Config:
    """测试配置类"""
    
    BASE_URL = "https://example-shop.com"
    TIMEOUT = 10
    BROWSER = "chrome"
    HEADLESS = False
    
    # 测试账户信息
    TEST_USER = {
        "email": "test@example.com",
        "password": "password123"
    }
    
    # 测试数据
    TEST_PRODUCT = {
        "name": "iPhone 14",
        "price": "999.99"
    }

基础页面类

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# pages/base_page.py
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By

class BasePage:
    """基础页面类"""
    
    def __init__(self, driver):
        self.driver = driver
        self.wait = WebDriverWait(driver, 10)
    
    def open(self, url):
        """打开页面"""
        self.driver.get(url)
    
    def find_element(self, locator):
        """查找元素"""
        return self.wait.until(EC.presence_of_element_located(locator))
    
    def click(self, locator):
        """点击元素"""
        element = self.wait.until(EC.element_to_be_clickable(locator))
        element.click()
    
    def input_text(self, locator, text):
        """输入文本"""
        element = self.find_element(locator)
        element.clear()
        element.send_keys(text)
    
    def get_text(self, locator):
        """获取元素文本"""
        element = self.find_element(locator)
        return element.text
    
    def is_element_visible(self, locator):
        """检查元素是否可见"""
        try:
            self.wait.until(EC.visibility_of_element_located(locator))
            return True
        except:
            return False

登录页面类

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# pages/login_page.py
from selenium.webdriver.common.by import By
from pages.base_page import BasePage

class LoginPage(BasePage):
    """登录页面"""
    
    # 页面元素定位
    EMAIL_INPUT = (By.ID, "email")
    PASSWORD_INPUT = (By.ID, "password")
    LOGIN_BUTTON = (By.XPATH, "//button[@type='submit']")
    ERROR_MESSAGE = (By.CLASS_NAME, "error-message")
    SUCCESS_MESSAGE = (By.CLASS_NAME, "success-message")
    
    def login(self, email, password):
        """执行登录操作"""
        self.input_text(self.EMAIL_INPUT, email)
        self.input_text(self.PASSWORD_INPUT, password)
        self.click(self.LOGIN_BUTTON)
    
    def get_error_message(self):
        """获取错误信息"""
        if self.is_element_visible(self.ERROR_MESSAGE):
            return self.get_text(self.ERROR_MESSAGE)
        return None
    
    def is_login_successful(self):
        """检查登录是否成功"""
        return self.is_element_visible(self.SUCCESS_MESSAGE)

登录测试用例

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# tests/test_login.py
import pytest
from pages.login_page import LoginPage
from utils.config import Config

class TestLogin:
    """登录功能测试类"""
    
    @pytest.fixture(autouse=True)
    def setup(self, driver):
        """测试前置条件"""
        self.driver = driver
        self.login_page = LoginPage(driver)
        self.login_page.open(f"{Config.BASE_URL}/login")
    
    def test_valid_login(self):
        """测试有效登录"""
        self.login_page.login(
            Config.TEST_USER["email"],
            Config.TEST_USER["password"]
        )
        assert self.login_page.is_login_successful()
    
    @pytest.mark.parametrize("email,password,expected_error", [
        ("", "password123", "邮箱不能为空"),
        ("invalid-email", "password123", "邮箱格式不正确"),
        ("test@example.com", "", "密码不能为空"),
        ("wrong@example.com", "wrongpass", "用户名或密码错误")
    ])
    def test_invalid_login(self, email, password, expected_error):
        """测试无效登录"""
        self.login_page.login(email, password)
        error_message = self.login_page.get_error_message()
        assert expected_error in error_message
    
    def test_login_form_elements(self):
        """测试登录表单元素存在性"""
        assert self.login_page.is_element_visible(self.login_page.EMAIL_INPUT)
        assert self.login_page.is_element_visible(self.login_page.PASSWORD_INPUT)
        assert self.login_page.is_element_visible(self.login_page.LOGIN_BUTTON)

商品搜索测试

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# pages/search_page.py
from selenium.webdriver.common.by import By
from pages.base_page import BasePage

class SearchPage(BasePage):
    """搜索页面"""
    
    SEARCH_INPUT = (By.NAME, "search")
    SEARCH_BUTTON = (By.CLASS_NAME, "search-btn")
    SEARCH_RESULTS = (By.CLASS_NAME, "product-item")
    NO_RESULTS_MESSAGE = (By.CLASS_NAME, "no-results")
    PRODUCT_TITLE = (By.CLASS_NAME, "product-title")
    
    def search_product(self, keyword):
        """搜索商品"""
        self.input_text(self.SEARCH_INPUT, keyword)
        self.click(self.SEARCH_BUTTON)
    
    def get_search_results_count(self):
        """获取搜索结果数量"""
        results = self.driver.find_elements(*self.SEARCH_RESULTS)
        return len(results)
    
    def get_first_product_title(self):
        """获取第一个商品标题"""
        return self.get_text(self.PRODUCT_TITLE)

# tests/test_search.py
import pytest
from pages.search_page import SearchPage
from utils.config import Config

class TestSearch:
    """搜索功能测试类"""
    
    @pytest.fixture(autouse=True)
    def setup(self, driver):
        self.driver = driver
        self.search_page = SearchPage(driver)
        self.search_page.open(Config.BASE_URL)
    
    def test_valid_search(self):
        """测试有效搜索"""
        self.search_page.search_product("iPhone")
        assert self.search_page.get_search_results_count() > 0
    
    def test_search_no_results(self):
        """测试无结果搜索"""
        self.search_page.search_product("不存在的商品")
        assert self.search_page.is_element_visible(self.search_page.NO_RESULTS_MESSAGE)
    
    @pytest.mark.parametrize("keyword", [
        "iPhone", "Samsung", "小米", "华为"
    ])
    def test_multiple_searches(self, keyword):
        """测试多个关键词搜索"""
        self.search_page.search_product(keyword)
        results_count = self.search_page.get_search_results_count()
        assert results_count >= 0  # 至少返回0个结果

页面对象模式(POM)

页面对象模式是自动化测试中的重要设计模式，它将页面元素和操作封装在独立的类中。

完整的POM实现

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# pages/product_page.py
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import Select
from pages.base_page import BasePage

class ProductPage(BasePage):
    """商品详情页"""
    
    # 商品信息元素
    PRODUCT_TITLE = (By.H1, "product-title")
    PRODUCT_PRICE = (By.CLASS_NAME, "price")
    PRODUCT_DESCRIPTION = (By.CLASS_NAME, "description")
    
    # 购买相关元素
    QUANTITY_SELECT = (By.NAME, "quantity")
    ADD_TO_CART_BUTTON = (By.ID, "add-to-cart")
    CART_SUCCESS_MESSAGE = (By.CLASS_NAME, "cart-success")
    
    # 评论相关元素
    REVIEWS_SECTION = (By.ID, "reviews")
    REVIEW_INPUT = (By.NAME, "review")
    SUBMIT_REVIEW_BUTTON = (By.ID, "submit-review")
    
    def get_product_info(self):
        """获取商品信息"""
        return {
            "title": self.get_text(self.PRODUCT_TITLE),
            "price": self.get_text(self.PRODUCT_PRICE),
            "description": self.get_text(self.PRODUCT_DESCRIPTION)
        }
    
    def add_to_cart(self, quantity=1):
        """添加到购物车"""
        # 选择数量
        quantity_select = Select(self.find_element(self.QUANTITY_SELECT))
        quantity_select.select_by_value(str(quantity))
        
        # 点击添加到购物车
        self.click(self.ADD_TO_CART_BUTTON)
        
        # 等待成功消息
        return self.is_element_visible(self.CART_SUCCESS_MESSAGE)
    
    def submit_review(self, review_text):
        """提交评论"""
        self.input_text(self.REVIEW_INPUT, review_text)
        self.click(self.SUBMIT_REVIEW_BUTTON)

购物车页面测试

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# tests/test_cart.py
import pytest
from pages.product_page import ProductPage
from pages.cart_page import CartPage
from utils.config import Config

class TestShoppingCart:
    """购物车功能测试"""
    
    @pytest.fixture(autouse=True)
    def setup(self, driver):
        self.driver = driver
        self.product_page = ProductPage(driver)
        self.cart_page = CartPage(driver)
    
    def test_add_single_product_to_cart(self):
        """测试添加单个商品到购物车"""
        # 打开商品页面
        self.product_page.open(f"{Config.BASE_URL}/product/1")
        
        # 添加到购物车
        success = self.product_page.add_to_cart(quantity=1)
        assert success
        
        # 验证购物车
        self.cart_page.open(f"{Config.BASE_URL}/cart")
        assert self.cart_page.get_cart_items_count() == 1
    
    def test_add_multiple_quantities(self):
        """测试添加多数量商品"""
        self.product_page.open(f"{Config.BASE_URL}/product/1")
        
        success = self.product_page.add_to_cart(quantity=3)
        assert success
        
        self.cart_page.open(f"{Config.BASE_URL}/cart")
        total_quantity = self.cart_page.get_total_quantity()
        assert total_quantity == 3
    
    def test_cart_total_calculation(self):
        """测试购物车总价计算"""
        # 添加多个商品
        products = [
            {"id": 1, "quantity": 2, "price": 99.99},
            {"id": 2, "quantity": 1, "price": 149.99}
        ]
        
        expected_total = 0
        for product in products:
            self.product_page.open(f"{Config.BASE_URL}/product/{product['id']}")
            self.product_page.add_to_cart(product["quantity"])
            expected_total += product["price"] * product["quantity"]
        
        self.cart_page.open(f"{Config.BASE_URL}/cart")
        actual_total = self.cart_page.get_total_price()
        assert actual_total == expected_total

测试报告生成

HTML报告配置

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# pytest.ini
[tool:pytest]
minversion = 6.0
addopts = -v --strict-markers --html=reports/report.html --self-contained-html
testpaths = tests
python_files = test_*.py
python_classes = Test*
python_functions = test_*
markers =
    smoke: 冒烟测试
    regression: 回归测试
    slow: 慢速测试

Allure报告集成

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# conftest.py 添加allure配置
import allure
import pytest
from selenium import webdriver

@pytest.hookimpl(tryfirst=True, hookwrapper=True)
def pytest_runtest_makereport(item, call):
    """生成测试报告钩子"""
    outcome = yield
    report = outcome.get_result()
    
    if report.when == "call" and report.failed:
        # 测试失败时自动截图
        driver = item.funcargs.get('driver')
        if driver:
            allure.attach(
                driver.get_screenshot_as_png(),
                name="失败截图",
                attachment_type=allure.attachment_type.PNG
            )

# 在测试中使用allure装饰器
import allure

class TestLoginWithAllure:
    """带Allure报告的登录测试"""
    
    @allure.epic("用户管理")
    @allure.feature("用户登录")
    @allure.story("正常登录流程")
    @allure.severity(allure.severity_level.CRITICAL)
    def test_valid_login_with_allure(self, driver):
        """测试有效登录 - Allure版本"""
        with allure.step("打开登录页面"):
            login_page = LoginPage(driver)
            login_page.open(f"{Config.BASE_URL}/login")
        
        with allure.step("输入登录凭证"):
            login_page.login(
                Config.TEST_USER["email"],
                Config.TEST_USER["password"]
            )
        
        with allure.step("验证登录结果"):
            assert login_page.is_login_successful()
            allure.attach(
                driver.get_screenshot_as_png(),
                name="登录成功截图",
                attachment_type=allure.attachment_type.PNG
            )

持续集成配置

GitHub Actions配置

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# .github/workflows/test.yml
name: 自动化测试

on:
  push:
    branches: [ main, develop ]
  pull_request:
    branches: [ main ]

jobs:
  test:
    runs-on: ubuntu-latest
    
    steps:
    - uses: actions/checkout@v3
    
    - name: 设置Python环境
      uses: actions/setup-python@v3
      with:
        python-version: '3.9'
    
    - name: 安装Chrome
      uses: browser-actions/setup-chrome@latest
    
    - name: 安装依赖
      run: |
        python -m pip install --upgrade pip
        pip install -r requirements.txt
    
    - name: 运行测试
      run: |
        pytest tests/ --html=reports/report.html --alluredir=allure-results
    
    - name: 生成Allure报告
      uses: simple-elf/allure-report-action@master
      if: always()
      with:
        allure_results: allure-results
        allure_history: allure-history
    
    - name: 上传测试报告
      uses: actions/upload-artifact@v3
      if: always()
      with:
        name: test-reports
        path: |
          reports/
          allure-report/

Docker配置

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# Dockerfile
FROM python:3.9-slim

# 安装系统依赖
RUN apt-get update && apt-get install -y \
    wget \
    gnupg \
    unzip \
    curl

# 安装Chrome
RUN wget -q -O - https://dl.google.com/linux/linux_signing_key.pub | apt-key add - \
    && echo "deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google-chrome.list \
    && apt-get update \
    && apt-get install -y google-chrome-stable

# 设置工作目录
WORKDIR /app

# 复制项目文件
COPY requirements.txt .
RUN pip install -r requirements.txt

COPY . .

# 运行测试
CMD ["pytest", "tests/", "--html=reports/report.html"]

最佳实践和进阶技巧

测试数据管理

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# utils/test_data.py
import json
import yaml
from pathlib import Path

class TestDataManager:
    """测试数据管理器"""
    
    def __init__(self, data_dir="test_data"):
        self.data_dir = Path(data_dir)
    
    def load_json_data(self, filename):
        """加载JSON测试数据"""
        file_path = self.data_dir / f"{filename}.json"
        with open(file_path, 'r', encoding='utf-8') as f:
            return json.load(f)
    
    def load_yaml_data(self, filename):
        """加载YAML测试数据"""
        file_path = self.data_dir / f"{filename}.yaml"
        with open(file_path, 'r', encoding='utf-8') as f:
            return yaml.safe_load(f)

# test_data/login_data.yaml
valid_users:
  - email: "user1@example.com"
    password: "password123"
    expected_result: "success"
  - email: "user2@example.com"
    password: "password456"
    expected_result: "success"

invalid_users:
  - email: ""
    password: "password123"
    expected_error: "邮箱不能为空"
  - email: "invalid-email"
    password: "password123"
    expected_error: "邮箱格式不正确"

失败重试机制

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# conftest.py
import pytest

@pytest.fixture(autouse=True)
def retry_failed_tests(request):
    """失败测试重试机制"""
    if request.node.rep_call.failed:
        # 重试逻辑
        pass

# 使用pytest-rerunfailures插件
# pip install pytest-rerunfailures
# pytest --reruns 3 --reruns-delay 2

并行测试执行

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# 安装pytest-xdist
# pip install pytest-xdist

# 并行执行测试
# pytest -n auto  # 自动检测CPU核心数
# pytest -n 4     # 使用4个进程

测试环境管理

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# utils/environment.py
import os
from enum import Enum

class Environment(Enum):
    DEV = "dev"
    TEST = "test"
    STAGING = "staging"
    PROD = "prod"

class EnvironmentConfig:
    """环境配置管理"""
    
    def __init__(self):
        self.current_env = Environment(os.getenv('TEST_ENV', 'test'))
        
    def get_base_url(self):
        """获取当前环境的基础URL"""
        urls = {
            Environment.DEV: "http://dev.example.com",
            Environment.TEST: "http://test.example.com",
            Environment.STAGING: "http://staging.example.com",
            Environment.PROD: "http://example.com"
        }
        return urls[self.current_env]
    
    def get_database_config(self):
        """获取数据库配置"""
        configs = {
            Environment.TEST: {
                "host": "test-db.example.com",
                "database": "test_db"
            },
            Environment.STAGING: {
                "host": "staging-db.example.com",
                "database": "staging_db"
            }
        }
        return configs.get(self.current_env, {})

性能测试集成

复制代码

# tests/test_performance.py
import time
import pytest
from selenium.webdriver.support.ui import WebDriverWait

class TestPerformance:
    """性能测试"""
    
    def test_page_load_time(self, driver):
        """测试页面加载时间"""
        start_time = time.time()
        
        driver.get("https://example.com")
        WebDriverWait(driver, 10).until(
            lambda d: d.execute_script("return document.readyState") == "complete"
        )
        
        load_time = time.time() - start_time
        assert load_time < 5.0, f"页面加载时间过长: {load_time}秒"
    
    def test_search_response_time(self, driver, search_page):
        """测试搜索响应时间"""
        search_page.open("https://example.com")
        
        start_time = time.time()
        search_page.search_product("iPhone")
        
        # 等待搜索结果出现
        WebDriverWait(driver, 10).until(
            lambda d: len(d.find_elements(*search_page.SEARCH_RESULTS)) > 0
        )
        
        response_time = time.time() - start_time
        assert response_time < 3.0, f"搜索响应时间过长: {response_time}秒"

数据库验证

复制代码

# utils/database.py
import sqlite3
import pymongo
from contextlib import contextmanager

class DatabaseHelper:
    """数据库操作助手"""
    
    def __init__(self, db_config):
        self.config = db_config
    
    @contextmanager
    def get_connection(self):
        """获取数据库连接"""
        if self.config['type'] == 'sqlite':
            conn = sqlite3.connect(self.config['path'])
        elif self.config['type'] == 'mysql':
            import mysql.connector
            conn = mysql.connector.connect(**self.config)
        
        try:
            yield conn
        finally:
            conn.close()
    
    def verify_user_created(self, email):
        """验证用户是否创建成功"""
        with self.get_connection() as conn:
            cursor = conn.cursor()
            cursor.execute("SELECT * FROM users WHERE email = ?", (email,))
            result = cursor.fetchone()
            return result is not None

# 在测试中使用数据库验证
def test_user_registration_with_db_verification(driver, db_helper):
    """测试用户注册并验证数据库"""
    # 执行注册操作
    registration_page = RegistrationPage(driver)
    test_email = f"test_{int(time.time())}@example.com"
    
    registration_page.register_user(
        email=test_email,
        password="password123"
    )
    
    # 验证UI显示成功
    assert registration_page.is_registration_successful()
    
    # 验证数据库中确实创建了用户
    assert db_helper.verify_user_created(test_email)

总结

本教程全面介绍了使用pytest和selenium进行Python自动化测试的完整流程，从环境搭建到高级技巧，涵盖了实际项目中的各个方面。

关键要点回顾

环境搭建: 正确配置Python环境、浏览器驱动和项目结构
pytest框架: 掌握基础测试、fixture机制和参数化测试
selenium操作: 学会元素定位、常用操作和等待机制
页面对象模式: 使用POM提高代码复用性和维护性
测试报告: 生成专业的HTML和Allure测试报告
持续集成: 配置CI/CD流程实现自动化测试
最佳实践: 应用进阶技巧提升测试质量和效率

Python自动化测试完整教程：pytest + selenium实战

目录

前言

环境搭建

安装Python和依赖包

浏览器驱动配置

项目结构搭建

pytest基础教程

pytest核心概念

基础测试示例

fixture机制深入

参数化测试

selenium基础教程

元素定位策略

常用操作封装

pytest + selenium实战项目

实战项目：电商网站测试

配置文件设置

基础页面类

登录页面类

登录测试用例

商品搜索测试

页面对象模式(POM)

完整的POM实现

购物车页面测试

测试报告生成

HTML报告配置

Allure报告集成

持续集成配置

GitHub Actions配置

Docker配置

最佳实践和进阶技巧

测试数据管理

失败重试机制

并行测试执行

测试环境管理

性能测试集成

数据库验证

总结

关键要点回顾