Senior Software Engineer - Test Interview Preparation

Round 1: Technical Screening

• What programming languages are you proficient in and how did you acquire this proficiency?
• What do you understand about test automation frameworks?
• What experience do you have with continuous integration and delivery?
• Explain the difference between functional and non-functional testing and describe the types of tests involved in each.
• What is test-driven development and have you had experience using it?
• What experience do you have with load and performance testing?
• What is your experience with testing APIs?
• How do you approach debugging a test failure?
• What does your process for writing automated tests entail?
• How do you measure code coverage to ensure thorough testing?

Answers:

Q: What programming languages are you proficient in and how did you acquire this proficiency?

A: I am proficient in Java, Python, C++, and JavaScript. I acquired proficiency in these languages through formal coursework as well as through industry experience. I have used Java extensively for server-side development, and Python for machine learning and data analysis tasks. C++ has been useful for performance-critical code, and JavaScript for both front-end web development and for test automation of web applications.

Q: What do you understand about test automation frameworks?

A: Test automation frameworks are tools that provide a structure for organizing and running automated tests. They can provide a standard way of writing tests, a mechanism for creating and managing test data, and test reporting and analysis features. Popular test automation frameworks include Selenium, Cucumber, and TestNG. Frameworks can be customized to fit the needs of the organization and the tests being run, and can be integrated with continuous integration and delivery tools.

Q: What experience do you have with continuous integration and delivery?

A: I have extensive experience with CI/CD, having used tools such as Jenkins and CircleCI in my past projects. I have set up and maintained pipelines that build, test, and deploy code automatically whenever a change is pushed to the repository. These pipelines integrate with various testing tools and frameworks to ensure that high-quality code is deployed to production. I have also used feature flags and canary releases to mitigate the risk of introducing bugs or performance issues in production environments.

Q: Explain the difference between functional and non-functional testing and describe the types of tests involved in each.

A: Functional testing involves testing a software application's features and functionality and ensures that each feature of the application works as intended. Types of tests involved in functional testing include unit testing, integration testing, system testing, regression testing, and acceptance testing. Non-functional testing, on the other hand, focuses on the application's capabilities such as performance, security, and usability. Types of tests involved in non-functional testing include load testing, stress testing, performance testing, security testing, and usability testing.

Q: What is test-driven development and have you had experience using it?

A: Test-driven development (TDD) is a software development process in which developers write automated tests before writing the code. This approach can help to ensure that the code meets the requirements and is easy to maintain. In TDD, each test written represents a small piece of functionality, which is then implemented in the code, and the process repeats. I have used TDD in some of my past projects, particularly for implementing algorithms and data structures where correctness is critical.

Q: What experience do you have with load and performance testing?

A: I have experience with load and performance testing and have used tools such as JMeter and Gatling to conduct tests on different applications. I have created test plans that simulate a specific number of users or transactions and analyze the application’s response time, network performance, and other relevant metrics. I have also analyzed the results and suggest optimization strategies to improve application performance.

Q: What is your experience with testing APIs?

A: I have experience with testing APIs using different tools such as Postman, SoapUI, and REST-assured. I verify functionality and HTTP response codes, as well as test API security by verifying authentication and authorization mechanisms, input validation, and error handling. I also ensure the API's compatibility with different data formats such as XML and JSON.

Q: How do you approach debugging a test failure?

A: Whenever a test fails, I first examine the failure message to understand the cause of the failure. Then, I investigate related log files and try to reproduce the error manually. If I am not able to reproduce the error, I add additional logging statements to gain more insight into the issue. If I cannot solve the problem after those steps, I reach out to other team members for assistance.

Q: What does your process for writing automated tests entail?

A: Initially, I analyze the requirements and identify all the scenarios and parameters to be tested. I collaborate with developers and other stakeholders to understand the code's inner workings and design the tests. Once I have created the test plan and test cases, I begin creating the tests in the testing framework and writing the necessary test data. Once implementation is complete, I refine the tests by adding assertions and improving the quality of test data. Finally, I verify that the tests are correctly aligned with the requirements and automated the test cases to be triggered as part of the CI/CD pipeline.

Q: How do you measure code coverage to ensure thorough testing?

A: I use tools such as JaCoCo and Cobertura to measure code coverage. These tools report the percentage of code lines and branches executed by the tests. I aim to achieve at least 80% code coverage in my test suites and continuously improve this metric by reviewing my code coverage reports during each testing cycle.

Round 2: Behavioral Interview

The behavioral round questions are designed to understand how you approach problem-solving, handle complex situations, and work in a team. Answer these questions using the Situation, Task, Action, Result (STAR) methodology.

• Describe a time when you had to solve a complex software testing problem.
• Have you ever disagreed with a stakeholder's requirements, and how did you approach the situation?
• Can you describe a time when you had to identify and prioritize defects during a testing cycle?
• How do you deal with a situation where a developer disagrees with a test case you have written?
• Describe a time when you had to communicate technical information to a non-technical person or audience.
• Have you ever faced a deadline while testing software? How did you manage to achieve the given timelines?
• Can you describe a time when you had to investigate an application's performance issue and found a performance bottleneck? How did you identify and fix it?
• Describe a time when you introduced a new testing process or testing tool that improved the team's efficiency.
• Have you mentored or coached a team member or colleague before? What was the situation, and what was the outcome?
• Can you describe a time when you worked under difficult circumstances, such as with an uncooperative client or in a high-pressure situation?

Answers:

Q: Describe a time when you had to solve a complex software testing problem.

A: While testing an e-commerce site, I encountered a critical performance issue which led to the application being completely unusable. I began by identifying the issue's root cause and concluded that the problem was caused by a specific API call. However, the cause of the issue was not clear. To get to the bottom of the problem, I profiled the application using various tools and located the point of slow code. I then discussed my observations with the development team, and we determined that data caching could solve the problem. I implemented the required caching mechanisms, reran the tests, and verified that the performance issues were resolved.

Q: Have you ever disagreed with a stakeholder's requirements, and how did you approach the situation?

A: Yes, once I was asked to remove a specific test from the test suite, but that test covered an important functionality of the application. I presented my concerns and the reasons why I created that particular test. I explained how it could cause issues that could negatively impact the company, such as data corruption or security vulnerabilities. I provided alternatives and suggested mitigation strategies to overcome the issue. Ultimately, the stakeholder understood the importance of the test and gave the green light to include it in the test suite.

Q: Can you describe a time when you had to identify and prioritize defects during a testing cycle?

A: Once, during a testing cycle, I came across several defects, some of which could cause critical components to fail. I decided to organize the defects into high, medium, and low priority based on the components affected, as well as their severity, impact, and frequency. I discussed the prioritization with the development team and the product owner to arrive at a consensus on resolving the identified defects. We addressed the critical defects first, followed by the high-priority and medium-priority defects. This method allowed us to reduce the risk of issues arising and ensured the in time delivery of a quality tested application.

Q: How do you deal with a situation where a developer disagrees with a test case you have written?

A: Whenever there is a disagreement between a developer and me about a test case, I discuss the details with the developer and listen to their reasoning. I make an effort to gain additional information and understand their perspective. If they raise a valid point, I make the necessary modifications to the test case. However, if I still feel the test needs to be executed as previously defined, I explain my reasoning to the developer and try to come to a mutual agreement.

Q: Describe a time when you had to communicate technical information to a non-technical person or audience.

A: I was working on a project where I had to explain test automation processes to a non-technical project sponsor. To make it more understandable and provide a visual representation, I created a flowchart that explained the process. I also used easy-to-understand language when explaining how the automation process worked. The project sponsor was able to understand the process better and appreciate the improvements achieved through automation.

Q: Have you ever faced a deadline while testing software? How did you manage to achieve the given timelines?

A: Yes, once, I had to test new functionality that had to be released within a short timeframe. I prioritized the tests based on criticality and requirement. Then, I created a test plan that included both manual and automated testing techniques while keeping the workflow smooth and precise. I worked longer hours and kept my testing cycle steps short, regular, and effective. This way, I was able to test thoroughly, meet the deadline, and deliver quality test results.

Q: Can you describe a time when you had to investigate an application's performance issue and found a performance bottleneck? How did you identify and fix it?

A: While working on an eCommerce application, I noticed that the checkout process was taking longer to complete, and the transaction time had increased. After analyzing the logs, I discovered that the root cause was due to non-optimized database queries. To fix it, I identified the slow statements, re-organized them, and added indexes to speed up their execution. Along with this, I identified and made changes to System Configuration, such as database pool size and server resource allocation, to optimize the application's performance and make the checkout process faster and smoother.

Q: Describe a time when you introduced a new testing process or testing tool that improved the team's efficiency.

A: I introduced Cucumber as a testing tool in one of my recent projects, which was previously the team's manual version. Our company had recently adopted BDD methodology, and Cucumber became more valuable in automating the manual scenarios and also easily integrated with the CI/CD pipeline. Also, there were several test cases that would fail due to unstable environment-specific data, which was resolved through the use of the Cucumber data table. The team's efficiency improved considerably as we had more automated test cases, and we were free to focus on new test scenarios and business requirements, leading to successful deployments to production faster.

Q: Have you mentored or coached a team member or colleague before? What was the situation, and what was the outcome?

A: Yes, I have mentored several employees in my present and past organizations. One notable example would be when I mentored a QA engineer in one of my earlier projects. They did not have programming experience to automate testing. I provided them with additional training, including coaching on various programming languages, and gave them access to resources that would be beneficial in an automation perspective. I provided them with real-life use cases, code templates, and practical exercises. As a result, the engineer was able to build a robust test suite quickly, and we were able to increase test coverage and reduce the time required to release the application to production.

Q: Can you describe a time when you worked under difficult circumstances, such as with an uncooperative client or in a high-pressure situation?

A: Once, when I was working for a client, I realized that the onus was almost entirely on the team to deliver code. Despite our best efforts, there were times when the client was unresponsive to our requests for information or feedback. The timeline was tight, and we were under constant pressure to deliver. We took it upon ourselves to gather information that would help us better understand their requirements. We also scheduled regular meetings to get feedback and raised our concerns when necessary. As a team, we kept our calm and focused our attention on the tasks that we could control. Through diligent prioritization of time and workload, we overcame the difficulties in delivering the project on time and with quality.

Round 3: Coding Interview

The coding round is designed to test your programming skills, problem-solving abilities, and knowledge of data structures and algorithms. We'll ask you questions on algorithm design and implementation, analyze your code, and assess your understanding of time and space complexity.

• Design an algorithm that finds all occurrences of a set of input strings in a larger string.
• Write a function that accepts a string and returns the reverse of it.
• Improve the following code to run in O(log n) time: `int sum = 0;for (int i = 0; i < n; i++) { for (int j = 0; j < i; j++) { sum++; }}`
• Given an array of integers, write a function that finds the maximum and minimum values, respectively.
• Implement a function that returns the nth element in the Fibonacci sequence.
• Given an array of integers, write a function to determine whether the array is monotonic, increasing, or decreasing.
• Write a function that takes a list of integers and returns a new list containing only the even numbers.
• Given a string, implement a function to find the first non-repeated character.
• Implement an algorithm to determine if a string has all unique characters.
• Given two strings, implement a function to check if one is a permutation of the other.

Answers:

Q: Design an algorithm that finds all occurrences of a set of input strings in a larger string.

A: One approach could be to iterate over the larger string and compare substrings of the same length as the target input strings. As soon as we find a match, we can store the index and search for the next target string from there. This would take O(n * m) time, where n is the length of the larger string and m is the maximum length of the target input strings. Another approach to achieve a better time complexity is to use trie data structure. We can insert all target strings into the trie and then traverse the trie at each index of the larger string. If we reach the end of a string in the trie, we have found a match and can add the index to the output list. This approach provides a faster runtime of O(n + k*m), where k is the number, and m is the maximum length of the target input strings.

Q: Write a function that accepts a string and returns the