Fixtures for browser setup/teardown in Selenium Python - Test Execution Trace

Test Overview

This test uses a fixture to open a browser before the test and close it after. It verifies that the page title is correct after navigating to the website.

Test Code - pytest

Selenium Python

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

@pytest.fixture
def browser():
    driver = webdriver.Chrome()
    yield driver
    driver.quit()

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

Execution Trace - 4 Steps

Step	Action	System State	Assertion	Result
1	Pytest fixture 'browser' starts: opens Chrome browser	Chrome browser window opens, ready for commands	—	PASS
2	Test navigates browser to 'https://example.com'	Browser loads the Example Domain webpage	—	PASS
3	Test checks that page title equals 'Example Domain'	Page title is 'Example Domain'	assert browser.title == 'Example Domain'	PASS
4	Test ends, fixture 'browser' teardown runs: closes browser	Chrome browser window closes	—	PASS

Failure Scenario

Failing Condition: Page title does not match 'Example Domain' after navigation

Execution Trace Quiz - 3 Questions

What does the fixture 'browser' do in this test?

A It runs the test code inside the browser

B It opens the browser before the test and closes it after

C It only opens the browser but does not close it

D It checks the page title automatically

Key Result

Using fixtures for browser setup and teardown ensures tests start with a fresh browser and clean up resources, making tests reliable and preventing leftover browser instances.

Practice

1. What is the main purpose of using a fixture for browser setup and teardown in Selenium tests?

easy

A. To avoid using assertions in tests

B. To write test cases faster without any setup

C. To automate opening and closing the browser before and after tests

D. To run tests only on one browser type

Solution

1. Step 1: Understand fixture role

   Fixtures help prepare the environment before tests and clean up after tests.

2. Step 2: Apply to browser context

   In Selenium, this means opening the browser before tests and closing it after.

3. Final Answer:

   To automate opening and closing the browser before and after tests -> Option C

4. Quick Check:

   Fixture = setup + teardown automation [OK]

Hint: Fixtures handle setup and cleanup automatically [OK]

Common Mistakes:

• Thinking fixtures replace test cases
• Believing fixtures remove need for assertions
• Assuming fixtures limit browser types

2. Which of the following is the correct way to define a pytest fixture for browser setup and teardown using yield?

easy

A. def browser():
driver = webdriver.Chrome()
yield driver
driver.quit()

B. def browser():
driver = webdriver.Chrome()
driver.quit()
yield driver

C. def browser():
yield webdriver.Chrome()
driver.quit()

D. def browser():
driver = webdriver.Chrome()
driver.close()
yield driver

Solution

1. Step 1: Understand yield usage in fixtures

   Yield separates setup (before yield) and teardown (after yield).

2. Step 2: Check correct order

   Setup: create driver; yield it; teardown: quit driver.

3. Final Answer:

   def browser(): driver = webdriver.Chrome() yield driver driver.quit() -> Option A

4. Quick Check:

   Setup before yield, teardown after yield [OK]

Hint: Setup before yield, teardown after yield in fixture [OK]

Common Mistakes:

• Calling quit before yield
• Using driver.close() instead of driver.quit() for teardown
• Yielding before creating driver

3. Given this fixture and test code, what will be printed when the test runs?

import pytest
from selenium import webdriver

@pytest.fixture
def browser():
    driver = webdriver.Chrome()
    print('Setup browser')
    yield driver
    print('Teardown browser')
    driver.quit()

def test_example(browser):
    print('Running test')

medium

A. Running test only

B. Running test\nSetup browser\nTeardown browser

C. Setup browser\nTeardown browser\nRunning test

D. Setup browser\nRunning test\nTeardown browser

Solution

1. Step 1: Trace fixture execution order

   Fixture runs setup code before yield, then test runs, then fixture runs teardown after yield.

2. Step 2: Match print statements order

   Prints 'Setup browser', then 'Running test', then 'Teardown browser'.

3. Final Answer:

   Setup browser\nRunning test\nTeardown browser -> Option D

4. Quick Check:

   Setup -> Test -> Teardown order [OK]

Hint: Fixture setup prints before test, teardown prints after [OK]

Common Mistakes:

• Assuming teardown runs before test
• Ignoring yield separates setup and teardown
• Thinking prints run all before test

4. What is wrong with this fixture code for browser setup and teardown?

@pytest.fixture
def browser():
    driver = webdriver.Chrome()
    driver.quit()
    yield driver

medium

A. Missing import statement for webdriver

B. Calling driver.quit() before yield closes browser too early

C. Yield should be inside a try-except block

D. Fixture should return driver instead of yield

Solution

1. Step 1: Analyze order of operations

   driver.quit() is called before yield, so browser closes before test uses it.

2. Step 2: Understand yield role

   Yield should come before teardown to keep browser open during test.

3. Final Answer:

   Calling driver.quit() before yield closes browser too early -> Option B

4. Quick Check:

   Teardown must be after yield [OK]

Hint: Teardown code must be after yield in fixture [OK]

Common Mistakes:

• Calling quit before yield
• Confusing yield with return
• Ignoring fixture import requirements

5. You want to run multiple tests using the same browser instance to save time. How should you modify the fixture to achieve this?

hard

A. Change fixture scope to 'module' so browser opens once per module

B. Add driver.quit() before yield to close browser early

C. Remove yield and return driver directly

D. Create a new fixture for each test to isolate browser

Solution

1. Step 1: Understand fixture scopes

   Default scope is 'function' which runs fixture per test; 'module' runs once per file.

2. Step 2: Apply scope to reuse browser

   Setting scope='module' opens browser once for all tests in module, saving time.

3. Final Answer:

   Change fixture scope to 'module' so browser opens once per module -> Option A

4. Quick Check:

   Fixture scope controls reuse [OK]

Hint: Use scope='module' to share browser across tests [OK]

Common Mistakes:

• Closing browser before tests run
• Removing yield breaks setup/teardown
• Creating new fixture per test wastes time