Find element by CSS selector in Selenium Python - Test Execution Trace

Test Overview

This test opens a web page and finds a button using a CSS selector. It then clicks the button and verifies the button's text changes as expected.

Test Code - Selenium

Selenium Python

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

class TestFindElementByCssSelector(unittest.TestCase):
    def setUp(self):
        self.driver = webdriver.Chrome()
        self.driver.get('https://example.com/button')

    def test_click_button_by_css_selector(self):
        driver = self.driver
        # Wait until button is present
        button = WebDriverWait(driver, 10).until(
            EC.presence_of_element_located((By.CSS_SELECTOR, 'button.submit-btn'))
        )
        button.click()
        # Verify button text changed
        updated_text = WebDriverWait(driver, 10).until(
            EC.text_to_be_present_in_element((By.CSS_SELECTOR, 'button.submit-btn'), 'Clicked')
        )
        self.assertTrue(updated_text)

    def tearDown(self):
        self.driver.quit()

if __name__ == '__main__':
    unittest.main()

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test starts and Chrome browser opens	Browser window is open and ready	-	PASS
2	Browser navigates to 'https://example.com/button'	Page with a button having class 'submit-btn' is loaded	-	PASS
3	Waits up to 10 seconds for button with CSS selector 'button.submit-btn' to be present	Button element is found on the page	Element located by CSS selector 'button.submit-btn' exists	PASS
4	Clicks the button found by CSS selector	Button is clicked, triggering text change	-	PASS
5	Waits up to 10 seconds for button text to change to include 'Clicked'	Button text updated to 'Clicked' or contains 'Clicked'	Button text contains 'Clicked'	PASS
6	Test ends and browser closes	Browser window is closed	-	PASS

Failure Scenario

Failing Condition: Button with CSS selector 'button.submit-btn' is not found within 10 seconds

Execution Trace Quiz - 3 Questions

What does the test wait for before clicking the button?

A Presence of the button element located by CSS selector

B Page title to contain 'Button'

C Button to be visible and enabled

D URL to change after clicking

Key Result

Always wait explicitly for elements using reliable locators like CSS selectors before interacting, to avoid flaky tests.