Retry mechanism for flaky tests in Selenium Python - Test Execution Trace

Test Overview

This test checks a login button on a webpage. It uses a retry mechanism to handle flaky failures by trying the test up to 3 times before failing.

Test Code - unittest

Selenium Python

import unittest
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.common.exceptions import NoSuchElementException
import time

class TestLoginButton(unittest.TestCase):
    MAX_RETRIES = 3

    def setUp(self):
        self.driver = webdriver.Chrome()
        self.driver.get('https://example.com/login')

    def test_login_button_present(self):
        retries = 0
        while retries < self.MAX_RETRIES:
            try:
                button = self.driver.find_element(By.ID, 'login-btn')
                self.assertTrue(button.is_displayed())
                break  # Test passed, exit retry loop
            except (NoSuchElementException, AssertionError):
                retries += 1
                if retries == self.MAX_RETRIES:
                    raise
                time.sleep(1)  # Wait before retrying

    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 WebDriver opens Chrome browser	Browser window opens at https://example.com/login	-	PASS
2	Test tries to find element with ID 'login-btn'	Page loaded, looking for login button	-	FAIL
3	Test catches NoSuchElementException, waits 1 second, retries (retry 1)	Still on login page, retrying element search	-	PASS
4	Test tries to find element with ID 'login-btn' again	Page loaded, looking for login button	-	PASS
5	Test asserts the login button is displayed	Login button found and visible	button.is_displayed() is True	PASS
6	Test passes and browser closes	Browser closed	-	PASS

Failure Scenario

Failing Condition: Login button with ID 'login-btn' is not found after 3 retries

Execution Trace Quiz - 3 Questions

What causes the test to retry finding the login button?

A NoSuchElementException or assertion failure

B Successful button click

C Page navigation to home

D Timeout waiting for page load

Key Result

Implementing a retry mechanism helps handle flaky tests caused by temporary issues like slow loading or element rendering delays, improving test reliability.