Test functions and classes in Selenium Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of a test function in Selenium Python?

A test function is a small piece of code that checks if a specific part of the web application works correctly. It uses Selenium commands to interact with the browser and assertions to verify expected results.

beginner

Why do we use test classes in Selenium Python?

Test classes group related test functions together. They help organize tests, share setup and cleanup code, and make tests easier to maintain and read.

beginner

What is the role of the setup method in a test class?

The setup method runs before each test function in the class. It prepares the environment, like opening a browser, so each test starts fresh and independent.

beginner

How do assertions work in test functions?

Assertions check if the actual result matches the expected result. If the assertion fails, the test stops and reports a failure, helping find bugs early.

beginner

Give an example of a simple test function using Selenium Python.

Example:
from selenium import webdriver

def test_title():
    driver = webdriver.Chrome()
    driver.get('https://example.com')
    assert 'Example Domain' in driver.title
    driver.quit()

This test opens a browser, goes to example.com, checks the page title, and closes the browser.

What does a test class help you do in Selenium Python?

A Automatically fix bugs in the code

B Run tests faster by skipping assertions

C Group related tests and share setup code

D Replace the need for test functions

Test classes group related tests and allow sharing setup and cleanup code to keep tests organized.

Which method usually runs before each test function in a test class?

A setup()

B teardown()

C main()

D __init__()

The setup() method prepares the environment before each test runs.

What happens if an assertion fails in a test function?

A The test continues running

B The test passes anyway

C The browser closes automatically

D The test stops and reports failure

An assertion failure stops the test and reports the failure to help identify issues.

Which Selenium command opens a web page in a browser?

A driver.open()

B driver.get()

C driver.load()

D driver.start()

driver.get(url) opens the specified web page in the browser.

Why is it important to close the browser after a test?

A To save computer memory and avoid interference with other tests

B To speed up the test execution

C To automatically fix errors

D To restart the test automatically

Closing the browser frees resources and ensures tests do not affect each other.

Explain how you would organize multiple Selenium tests using test functions and classes.

Think about keeping tests clean and easy to manage.

Describe the role of assertions in test functions and what happens when they fail.

Assertions are like checkpoints in your test.

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