Parallel execution in CI in Selenium Python - Build an Automation Script

Run two simple Selenium tests in parallel on CI

Preconditions (4)

Step 1: Create two simple Selenium test functions that open https://example.com and check the page title

Step 2: Configure pytest to run tests in parallel using pytest-xdist with 2 workers

Step 3: Push the test code and pytest configuration to the CI repository

Step 4: Trigger the CI pipeline to run the tests

Step 5: Observe that both tests run at the same time (in parallel) in the CI logs

Step 6: Verify that both tests pass successfully

✅ Expected Result: Both Selenium tests run simultaneously in the CI environment and pass, confirming parallel execution works.

Automation Requirements - pytest with Selenium WebDriver and pytest-xdist

Assertions Needed:

Verify page title is exactly 'Example Domain' in both tests

Verify both tests complete successfully in parallel

Best Practices:

Use explicit waits if needed (though example.com loads fast)

Use pytest fixtures for WebDriver setup and teardown

Avoid sharing WebDriver instances between tests

Use pytest-xdist -n 2 to run tests in parallel

Keep tests independent and stateless

Automated Solution

Selenium Python

import pytest
from selenium import webdriver
from selenium.webdriver.chrome.service import Service
from selenium.webdriver.common.by import By
from selenium.webdriver.chrome.options import Options

@pytest.fixture
 def driver():
    options = Options()
    options.add_argument('--headless')
    options.add_argument('--no-sandbox')
    options.add_argument('--disable-dev-shm-usage')
    service = Service()
    driver = webdriver.Chrome(service=service, options=options)
    yield driver
    driver.quit()


def test_example_domain_title_1(driver):
    driver.get('https://example.com')
    assert driver.title == 'Example Domain'


def test_example_domain_title_2(driver):
    driver.get('https://example.com')
    assert driver.title == 'Example Domain'

# To run in parallel, use the command:
# pytest -n 2 test_parallel.py

The driver fixture creates a new Chrome WebDriver instance for each test, ensuring tests do not share browser sessions.

Both test_example_domain_title_1 and test_example_domain_title_2 open https://example.com and assert the page title is exactly 'Example Domain'.

Running pytest -n 2 test_parallel.py uses pytest-xdist to run the two tests in parallel with 2 workers.

This setup is ideal for CI environments where parallel execution speeds up test runs.

Headless Chrome options are used to run browsers without UI, suitable for CI servers.

Common Mistakes - 4 Pitfalls

Sharing a single WebDriver instance across multiple tests

Not using pytest-xdist or equivalent to enable parallelism

Hardcoding waits or using time.sleep instead of explicit waits

Running tests with visible browser windows in CI

Bonus Challenge

Now add data-driven testing with 3 different URLs and verify their titles in parallel

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