Test functions and classes in Selenium Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of a simple Selenium test function

What will be the test result when running this Selenium test function using pytest?

Selenium Python

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

def test_google_title():
    driver = webdriver.Chrome()
    driver.get('https://www.google.com')
    title = driver.title
    driver.quit()
    assert 'Google' in title

A Test fails because the URL is incorrect

B Test fails because driver.quit() is called before getting the title

C Test raises a NoSuchElementException

D Test passes because the page title contains 'Google'

💡 Hint

Think about what driver.title returns after loading the page.

The test opens Google's homepage, gets the title which contains 'Google', then asserts this condition. The driver.quit() is called after getting the title, so it does not affect the assertion.

❓ assertion

intermediate

Correct assertion for checking element text

Which assertion correctly verifies that a web element's text is exactly 'Submit' in a Selenium test?

Selenium Python

element = driver.find_element(By.ID, 'submit-btn')
text = element.text

A assert text is 'Submit'

B assert 'Submit' in text

C assert text == 'Submit'

D assert text != 'Submit'

💡 Hint

Use the equality operator to check exact match.

The assertion 'assert text == 'Submit'' checks that the element's text exactly matches 'Submit'. Using 'in' checks for substring, '!=' is the opposite, and 'is' checks identity which is not reliable for strings.

🔧 Debug

advanced

Identify the error in this Selenium test class

What error will occur when running this Selenium test class with pytest?

Selenium Python

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

class TestLogin:
    def setup_method(self):
        self.driver = webdriver.Chrome()

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

    def test_login(self):
        self.driver.get('https://example.com/login')
        username = self.driver.find_element(By.ID, 'username')
        password = self.driver.find_element(By.ID, 'password')
        username.send_keys('user')
        password.send_keys('pass')
        self.driver.find_element(By.ID, 'submit').click()
        assert 'Dashboard' in self.driver.title

A NoSuchElementException if elements are not found

B AttributeError because setup_method is not named correctly

C No error, test runs and passes if page loads correctly

D TypeError due to missing self parameter in test_login

💡 Hint

Consider what happens if the page elements are missing or IDs are incorrect.

If the elements with IDs 'username', 'password', or 'submit' do not exist on the page, Selenium raises NoSuchElementException. The setup and teardown methods are correctly named and used.

❓ framework

advanced

Best practice for Selenium test class setup and teardown

Which code snippet correctly implements setup and teardown for a Selenium test class using pytest conventions?

A

class TestExample:
    def setUp(self):
        self.driver = webdriver.Chrome()
    def tearDown(self):
        self.driver.quit()

B

class TestExample:
    def setup_method(self):
        self.driver = webdriver.Chrome()
    def teardown_method(self):
        self.driver.quit()

C

class TestExample:
    def setup(self):
        self.driver = webdriver.Chrome()
    def teardown(self):
        self.driver.quit()

D

class TestExample:
    def before_all(self):
        self.driver = webdriver.Chrome()
    def after_all(self):
        self.driver.quit()

💡 Hint

Pytest uses setup_method and teardown_method for per-test setup/teardown.

Pytest recognizes setup_method and teardown_method for setup and cleanup before and after each test method. 'setup' and 'setUp' are unittest conventions, and 'before_all'/'after_all' are not pytest standard.

🧠 Conceptual

expert

Understanding test isolation in Selenium test classes

Why is it important to create a new WebDriver instance in the setup method before each test instead of reusing the same driver instance across multiple tests?

A To ensure each test runs in a clean browser state, avoiding side effects from previous tests

B To reduce the total test execution time by reusing browser sessions

C Because WebDriver instances cannot be reused due to API limitations

D To avoid memory leaks caused by closing the browser too often

💡 Hint

Think about how leftover data or state can affect test results.

Creating a new WebDriver instance for each test ensures tests do not affect each other by sharing browser state like cookies, cache, or session data. This isolation improves test reliability and repeatability.

Practice

1. What is the main purpose of using test functions and classes in Selenium Python testing?

easy

A. To organize tests clearly and run them easily

B. To make the code run faster

C. To avoid writing any assertions

D. To skip browser setup

Solution

1. Step 1: Understand test organization

   Test functions and classes help group related tests logically.

2. Step 2: Recognize ease of running tests

   Using classes and functions allows running tests easily with frameworks like unittest.

3. Final Answer:

   To organize tests clearly and run them easily -> Option A

4. Quick Check:

   Test organization = To organize tests clearly and run them easily [OK]

Hint: Tests group checks for clarity and easy running [OK]

Common Mistakes:

• Thinking tests speed up code execution
• Believing assertions are optional
• Ignoring setup and teardown roles

2. Which of the following is the correct way to define a test method inside a unittest.TestCase class in Selenium Python?

easy

A. def test_example(self):

B. def example_test():

C. def TestExample(self):

D. def _test_example(self):

Solution

1. Step 1: Recall unittest naming conventions

   Test methods must start with 'test' and accept 'self' as first parameter.

2. Step 2: Check method definitions

   Only 'def test_example(self):' follows correct naming and signature.

3. Final Answer:

   def test_example(self): -> Option A

4. Quick Check:

   Method name starts with 'test' and has 'self' [OK]

Hint: Test methods start with 'test' and include self [OK]

Common Mistakes:

• Omitting 'self' parameter
• Not starting method name with 'test'
• Using uppercase 'Test' prefix

3. What will be the output when running this test code snippet?

import unittest

class MyTest(unittest.TestCase):
    def test_pass(self):
        self.assertEqual(2 + 2, 4)

    def test_fail(self):
        self.assertTrue(False)

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

medium

A. Both tests pass

B. One test passes, one test fails

C. Both tests fail

D. Syntax error occurs

Solution

1. Step 1: Analyze test_pass method

   assertEqual(2 + 2, 4) is True, so test_pass passes.

2. Step 2: Analyze test_fail method

   assertTrue(False) fails, so test_fail fails.

3. Final Answer:

   One test passes, one test fails -> Option B

4. Quick Check:

   One True, one False assertion = One test passes, one test fails [OK]

Hint: Check each assertion's truth to predict pass/fail [OK]

Common Mistakes:

• Assuming all tests pass
• Ignoring assertTrue(False) fails
• Expecting syntax errors

4. Identify the error in this Selenium Python unittest code:

import unittest
from selenium import webdriver

class TestLogin(unittest.TestCase):
    def setUp(self):
        self.driver = webdriver.Chrome()

    def test_login(self):
        self.driver.get('http://example.com')
        self.assertIn('Example', self.driver.title)

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

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

medium

A. webdriver.Chrome() requires path argument

B. Missing call to super() in setUp and tearDown

C. No error; code is correct

D. assertIn should be assertEquals

Solution

1. Step 1: Review setup and teardown methods

   setUp creates driver; tearDown quits it properly.

2. Step 2: Check assertion and webdriver usage

   assertIn checks substring in title correctly; webdriver.Chrome() works if driver is in PATH.

3. Final Answer:

   No error; code is correct -> Option C

4. Quick Check:

   Standard unittest setup and teardown used [OK]

Hint: Check if setup/teardown and assertions follow unittest rules [OK]

Common Mistakes:

• Assuming webdriver.Chrome() always needs path
• Confusing assertIn with assertEquals
• Forgetting to quit driver in tearDown

5. You want to run multiple Selenium tests that share the same browser setup and cleanup. Which unittest structure best achieves this?

hard

A. Call unittest.main() inside each test method

B. Write separate test functions without any setup or teardown

C. Create a new webdriver instance inside each test method

D. Use a TestCase class with setUpClass and tearDownClass class methods

Solution

1. Step 1: Understand shared setup/cleanup needs

   setUpClass and tearDownClass run once for all tests in a class, ideal for shared browser setup.

2. Step 2: Evaluate other options

   Separate functions lack shared setup; new webdriver per test is inefficient; unittest.main() runs all tests, not per method.

3. Final Answer:

   Use a TestCase class with setUpClass and tearDownClass class methods -> Option D

4. Quick Check:

   Shared setup/cleanup = setUpClass/tearDownClass [OK]

Hint: Use setUpClass/tearDownClass for shared browser setup [OK]

Common Mistakes:

• Creating driver in each test wastes resources
• Calling unittest.main() multiple times causes errors
• Skipping setup causes flaky tests