Environment Setup

1. Install a supported browser (Chrome, Firefox, Edge, Safari).
2. Add the Python bindings:

   pip install selenium
   

3. Download the matching driver executable:
   • Chrome → chromedriver
   • Firefox → geckodriver
   • Edge → msedgedriver
   • Safari → safaridriver (built-in)

Place the driver in a directory listed in your PATH, or keep it next to the Python interpreter.

Quick Start Session

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

driver = webdriver.Chrome()
driver.implicitly_wait(10)

Browser Metadata

Navigation & Window Control

driver.get("https://example.com")
driver.refresh()
driver.back()
driver.forward()

driver.maximize_window()
driver.minimize_window()
driver.set_window_size(800, 600)
driver.fullscreen_window()

driver.close()   # Close active tab
driver.quit()    # Kill browser process

Working with Web Elements

Attributes

Actions

search_box = driver.find_element(By.ID, "q")
search_box.clear()
search_box.send_keys("selenium")
search_box.submit()

button = driver.find_element(By.CSS_SELECTOR, "button.primary")
button.click()

Locator Strategies

Use explicit waits for robustness:

from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

try:
    elem = WebDriverWait(driver, 10).until(
        EC.presence_of_element_located((By.NAME, "username"))
    )
except TimeoutException:
    print("Element not found")

find_element raises NoSuchElementException when absent; find_elements returns an empty list.

Running Tests with pytest

pytest tests/test_login.py
pytest tests/ --html=report.html --self-contained-html

pytest automatically closes the browser when the process ends; call driver.quit() explicitly to avoid orpahned drivers.

Common Pitfalls

• StaleElementReferenceException: The DOM changed after the element was located. Re-query the element after navigation, refresh, or form submission.
• Timing issues: Use explicit waits instead of fixed sleep calls.
• Driver mismatch: Ensure driver version matches browser version exactly.

# Safe pattern
def safe_click(driver, locator):
    return WebDriverWait(driver, 10).until(
        EC.element_to_be_clickable(locator)
    ).click()