selenium

selenium Best Practices

This guide outlines the definitive best practices for using Selenium with Python. Adhere to these rules to ensure your automation scripts are robust, maintainable, and performant.

1. Code Organization: Page Object Model (POM)

Always structure your Selenium code using the Page Object Model (POM). This separates UI elements and interactions from your test or scraping logic, making your code highly maintainable and reusable.

❌ BAD: Logic and locators mixed

from selenium import webdriver
from selenium.webdriver.common.by import By

driver = webdriver.Chrome()
driver.get("https://example.com/login")
driver.find_element(By.ID, "username").send_keys("user")
driver.find_element(By.ID, "password").send_keys("pass")
driver.find_element(By.XPATH, "//button[text()='Login']").click()
# ... more logic

✅ GOOD: Page Object Model

# pages/base_page.py
from selenium.webdriver.remote.webdriver import WebDriver
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:
    def __init__(self, driver: WebDriver, timeout: int = 10):
        self.driver = driver
        self.wait = WebDriverWait(driver, timeout)

    def _find_element(self, by: By, value: str):
        return self.wait.until(EC.presence_of_element_located((by, value)))

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

class LoginPage(BasePage):
    URL = "https://example.com/login"
    _USERNAME_INPUT = (By.ID, "username")
    _PASSWORD_INPUT = (By.ID, "password")
    _LOGIN_BUTTON = (By.XPATH, "//button[text()='Login']")

    def open(self):
        self.driver.get(self.URL)

    def login(self, username, password):
        self._find_element(*self._USERNAME_INPUT).send_keys(username)
        self._find_element(*self._PASSWORD_INPUT).send_keys(password)
        self._find_element(*self._LOGIN_BUTTON).click()

# tests/test_login.py (or main scraping script)
from selenium import webdriver
from pages.login_page import LoginPage

def test_successful_login():
    driver = webdriver.Chrome()
    try:
        login_page = LoginPage(driver)
        login_page.open()
        login_page.login("valid_user", "valid_pass")
        assert "dashboard" in driver.current_url # Example assertion
    finally:
        driver.quit()