The Complete Guide to Acing Your Senior Software Development Engineer in Test Interview

Landing a job as a Senior Software Development Engineer in Test (SDET) is a major career milestone. As one of the most coveted quality assurance roles in tech, competition is fierce. You’ll be up against some of the industry’s top talent.

To stand out from the pack, astute preparation is key. The make-or-break for most applicants is the dreaded interview. Mess this up, and your application gets binned faster than you can say ” software testing.” Ace it, however, and you could soon be enjoying those sweet senior-level perks.

But what will hiring managers actually ask? And how do you craft winning responses? This comprehensive guide has all the answers

I’ve analyzed the most commonly asked SDET interview questions, providing tips and sample responses to each one. Follow this advice and you’ll walk into that interview room feeling ready and confident. Let’s get started!

The Most Important SDET Interview Questions and Answers

1. What’s the difference between an SDET and a manual software tester?

This role-focused question is likely to come up early in the interview. Essentially, they want to confirm you understand the key responsibilities and skills needed for the SDET position specifically.

Tips

• Emphasize automation. This is the prime distinction between SDETs and manual testers.

• Discuss coding abilities Proficiency in languages like Python and Java is mandatory for SDETs.

• Highlight advanced technical skills needed for test automation frameworks.

Sample Response:

The fundamental difference is that an SDET specializes in test automation, while a manual tester performs testing manually. As an SDET, I possess strong coding skills which I utilize to develop automated test scripts and frameworks. My expertise lies in leveraging tools like Selenium to build robust automation solutions.

In contrast, a manual tester may not necessarily have strong coding abilities. Their focus is on documenting test cases, executing them manually, identifying issues, and reporting defects. My role as an SDET involves automating many of these repetitive tasks to improve efficiency and coverage.

2. How would you define ad hoc testing?

Ad hoc testing is an important concept that speaks to your fundamental understanding of software testing principles. When asked to define it, be sure to highlight:

Tips:

• The informal, unstructured nature of this testing technique

• Objectives like trying to break the software to uncover hidden defects

• The fact that it’s done without planning or documentation

Sample Response:

Ad hoc testing refers to an informal testing approach without detailed planning, documentation, or structured processes. As the name suggests, it is performed on an ad hoc basis to supplement formal testing efforts.

The objective is to discover bugs and defects by actively experimenting with the software in an unstructured manner and trying to break it in every possible way. This provides insights that may be missed during structured tests.

Ad hoc tests are carried out without reference to any test plans or cases. The focus is on subjective testing based on the tester’s knowledge and intuition rather than formal test conditions. It aims to improve overall software quality by uncovering unanticipated issues.

3. What’s the difference between priority and severity when classifying software defects?

This seems like a simple definition question but it demonstrates your nuanced understanding of defect management, a core SDET skill. Make sure you clearly articulate the distinction.

Tips:

• Priority relates to the business impact of the defect
• Severity describes its technical implications on the system

Sample Response:

Though often used interchangeably, priority and severity have distinct meanings in software defect management:

Priority indicates the business criticality of a defect and measures its potential impact on key business functions if it is not fixed. It relates to the importance of resolving the issue based on factors like financials, operations, and compliance.

Severity describes the degree to which a defect affects or degrades the quality of the system. It represents the technical implications such as data loss, system instability, crashes etc.

Priority focuses on the business perspective while severity captures the technical standpoint. A severity 1 defect may not necessarily have priority 1 if it does not significantly impact business goals. Correct classification helps developers and testers prioritize work accordingly.

4. What are the key responsibilities and skills needed as an SDET?

This is your chance to demonstrate that your experience and abilities align perfectly with the needs of the role. Focus on must-have skills like automation, coding, analytical thinking, communication, and tools proficiency.

Tips:

• Don’t just list generic responsibilities – connect them back to your proven skills and experience.

• Quantify your work with stats/numbers to back up claims of proficiency.

Sample Response:

Key SDET responsibilities that leverage my expertise include:

• Developing and executing automated test scripts using Selenium – I have automated over 2000 test cases which enhanced coverage by 75%.

• Building scalable test automation frameworks from scratch using Java and TestNG – My framework reduced repeat testing efforts by half.

• Performing root cause analysis for complex software defects and advising developers on fixes – My troubleshooting helped decrease high priority bugs by 35% last year.

• Evaluating quality metrics and reports to identify areas for improvement – My analysis led to modified source code lowering technical debt.

• Communicating efficiently across teams to enable collaboration – My clear documentation received praise from 5 different development teams.

Fundamental skills I possess are coding languages like Java and Python, designing test strategies, defect tracking tools like JIRA, understanding of SDLC, and problem-solving attitude.

5. Walk me through a typical day as an SDET.

This open-ended question allows you to take the interviewer through your ideal work day as an SDET. Structure your response clearly, highlighting crucial activities.

Tips:

• Include both individual contributor and collaborative activities.

• Demonstrate your process orientation and highlight productivity/prioritization tactics.

• Quantify or qualify how your daily activities contribute to team/company goals.

Sample Response:

Here’s a snapshot of my typical day as an SDET:

• I start the day by reviewing and prioritizing test cases and defects in our tracking system based on factors like criticality, deadlines, and team capacity. This enables optimal task allocation.

• Next, I work on test automation development – writing new automated scripts or enhancing existing ones. I aim to automate at least 10 test cases before lunchtime.

• Post lunch is when I collaborate with developers, BAs and product managers to discuss upcoming features, changes, and associated test requirements.

• In the second half of the day, I focus on test execution – running automation suites and performing exploratory tests to uncover defects. I log all defects systematically with steps to reproduce.

• Before I wrap up, I ensure my test status reports and metrics are updated for stakeholder review. I also take time to organize and plan for the next day.

• Overall, my goal is to complete both independent contributions like automation as well as collaborative activities like meetings in a productive, time-bound manner.

Automation Testing Questions

Automation is the bread and butter of any SDET role. Be prepared for a barrage of questions testing your knowledge to the limits.

6. How do you determine which test cases to automate?

This question demonstrates your strategic thinking abilities. The key is to automate intelligently based on objective parameters.

Tips:

• Discuss criteria like frequency of execution, time required for manual testing, criticality of the feature etc.

• Mention the 80/20 rule i.e. automating 20% of test cases that cover 80% of use cases.

Sample Response:

I follow a defined framework to determine which test cases provide the best ROI for automation.

Firstly, I analyze execution frequency – test cases that need to be rerun often during regression testing are strong automation candidates.

Secondly, I look at execution time – long test cases that take over 20 minutes manually are recommended for automation.

Critical user journeys are also prime for automation irrespective of execution frequency or time.

Additionally, I leverage Pareto analysis – automating the 20% of test cases that cover 80% of system functionality maximizes coverage while minimizing effort. By optimizing in this manner, I ensure maximum automation coverage and increased efficiency.

7. What challenges did you face while automating user interfaces and how did you handle them?

Don’t be afraid to demonstrate failures you faced provided you can discuss how you overcame them. This indicates resilience which managers love to see.

Tips:

• User interfaces tend to change frequently during development, leading to test script maintenance challenges – highlight ways to minimize effort here.

• Cross-browser/device testing requires extensive configurations. Focus on solutions like cloud-based tools.

• Responsive UI testing on different screen sizes can be tricky. Discuss your optimal approaches.

Sample Response:

Automating user interfaces comes with its share of challenges. Here are two I faced and how I handled them:

Firstly, UIs tend to change frequently during development, leading to broken test scripts that require continuous maintenance. To address this, I started utilizing object loc