Top 10 Python Coding Interview Questions and Answers for Test Automation & SDET Roles

 Python has become a top choice for test automation and Software Development Engineer in Test (SDET Course) roles due to its simplicity, readability, and robust library ecosystem. To succeed in Python-based coding interviews, you need a deep understanding of its core principles and real-world applications in automation. Below are the top 10 Python coding questions and answers to help you excel in your next interview.

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Answer:Python’s key features that make it perfect for test automation include:

• A simple and readable syntax that accelerates development.
• Comprehensive libraries like unittest, pytest, and selenium tailored for testing.
• Compatibility across platforms, enabling test scripts to run seamlessly.
• Smooth integration with tools like Jenkins, Docker, and CI/CD pipelines.

2. What Python data types are frequently used in test automation?

Answer:Commonly used data types include:

• String: Handles textual data such as URLs and XPath expressions.
• List: Stores collections of items, useful for iterating over test inputs.
• Dictionary: Maps key-value pairs, ideal for managing test configurations.
• Set: Ensures unique test data by removing duplicates.
• Tuple: Stores immutable sequences, great for fixed datasets.

3. How do you implement exception handling in Python, and why is it crucial for automation?

Answer:Exception handling prevents abrupt termination of test scripts. Use try-except blocks as shown:try: driver.get("https://example.com") except Exception as e: print(f"Error occurred: {e}")

Benefits include:

• Preventing script crashes.
• Logging errors for debugging purposes.
• Ensuring the continuation of subsequent test cases.

4. Differentiate between shallow copy and deep copy in Python.

Answer:

• Shallow Copy: Creates a new object but references the original data elements.
• Deep Copy: Creates a new object and recursively copies all elements, avoiding unintended modifications.

Example:import copyoriginal = [[1, 2], [3, 4]] shallow = copy.copy(original) deep = copy.deepcopy(original)

Shallow copies may inadvertently alter data in the original object, which deep copies prevent.

5. How do you write a test case using Python’s unittest module?

Answer:Example of a basic test case:import unittest class TestExample(unittest.TestCase): def test_addition(self): self.assertEqual(1 + 1, 2) if __name__ == "__main__": unittest.main()

unittest provides:

• A consistent structure for test scripts.
• Support for test discovery and execution.
• Built-in capabilities for setup, teardown, and assertions.

6. What are the advantages of using Python’s pytest framework?

Answer:pytest enhances test automation with:

• Simple and intuitive syntax for writing tests.
• Parametrization for running the same test with different data inputs.
• Built-in fixtures for managing setup and teardown processes.
• A vast plugin ecosystem to extend functionality.

Example of a parametrized test:import pytest @pytest.mark.parametrize("input, expected", [(5, True), (-1, False)]) def test_is_positive(input, expected): assert (input > 0) == expected

7. How do you manage dependencies in Python testing projects?

Answer:Tools like pip and virtualenv help manage dependencies effectively:

• Define dependencies in requirements.txt:selenium==4.1.0pytest==7.1.0
• Install dependencies with:pip install -r requirements.txt

Virtual environments ensure isolated environments, avoiding dependency conflicts.

8. What is the difference between is and == in Python?

Answer:

• is checks for object identity (whether two references point to the same object).
• == checks for value equality (whether two objects hold the same value).

Example:x = [1, 2]y = [1, 2] print(x == y) # True (same values) print(x is y) # False (different objects)

9. How can Selenium be used with Python for web test automation?

Answer:Selenium simplifies web browser automation. Example script:from selenium import webdriver driver = webdriver.Chrome() driver.get("https://example.com") # Locate and interact with an element element = driver.find_element_by_name("search") element.send_keys("Automation Testing") driver.quit()

Features include:

• Multi-browser compatibility.
• Handling dynamic web elements using XPath and CSS selectors.

10. What are Python’s best practices for writing maintainable test scripts?

Answer:

• Follow PEP 8: Maintain consistent and readable code.
• Modular Design: Create reusable functions and classes for better organization.
• Meaningful Names: Use clear and descriptive variable, function, and class names.
• Logging: Replace print statements with the logging module for better traceability.
• Version Control: Track changes using Git to manage revisions effectively.

Conclusion

Excelling in Python-based coding interviews for SDET Training and test automation roles requires mastering both theoretical concepts and practical implementations. The questions above highlight key areas of focus to help you demonstrate your expertise and stand out in interviews.

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