下面是一个完整的脚本，可以用pytest运行，它定义了setUp()和tearDown()方法，这样浏览器就可以在测试开始和结束时自动打开和关闭：（这是使用fixture的替代方案，因为pytest可以与unittest.TestCase结合使用，这可能有助于更好地构建内容，以确保在测试结束时关闭浏览器。

import sys
import time
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.ui import WebDriverWait
from unittest import TestCase

class SeleniumClass(TestCase):
    def setUp(self):
        self.driver = None
        options = webdriver.ChromeOptions()
        options.add_argument("--disable-notifications")
        if "linux" in sys.platform:
            options.add_argument("--headless=new")
        options.add_experimental_option(
            "excludeSwitches", ["enable-automation", "enable-logging"],
        )
        prefs = {
            "credentials_enable_service": False,
            "profile.password_manager_enabled": False,
        }
        options.add_experimental_option("prefs", prefs)
        self.driver = webdriver.Chrome(options=options)

    def tearDown(self):
        if self.driver:
            try:
                if self.driver.service.process:
                    self.driver.quit()
            except Exception:
                pass

    def test_login(self):
        self.driver.get("https://www.saucedemo.com")
        by_css = By.CSS_SELECTOR  # "css selector"
        element = WebDriverWait(self.driver, 10).until(
            EC.element_to_be_clickable((by_css, "#user-name"))
        )
        element.send_keys("standard_user")
        element = WebDriverWait(self.driver, 10).until(
            EC.element_to_be_clickable((by_css, "#password"))
        )
        element.send_keys("secret_sauce")
        element.submit()
        WebDriverWait(self.driver, 10).until(
            EC.visibility_of_element_located((by_css, "div.inventory_list"))
        )
        time.sleep(1)

# When run with "python" instead of "pytest" or "python -m unittest"
if __name__ == "__main__":
    from unittest import main
    main()