Top 25 Most Asked SDET Interview Questions and Answers

1) What is SDET?

SDET is an acronym that stands for "Software Development Engineer in Test." It is a testing role that is getting more popular nowadays in the Agile methodologies. It is also known as Software Design Engineer in Test.

SDET was first introduced by Microsoft and Google when they observed that the testing team alone could not test the build so quickly due to the short test cycles. So, agile development was introduced where product development and test cycle have to go parallel to fulfill the overall product's objective. This was how the SDET role came into existence.

The role of an SDET is different from a routine test engineer because SDET must have a good sense of quality and testing and a good knowledge of coding. In simple words, we can say that it is a hybrid of a software developer and a test engineer.

2) What are the prominent roles and responsibilities of SDET?

As SDET combines software developers and testers, they have to be involved in both software development and testing. That's why an SDET has good knowledge of software testing, programming languages, analytical skills, and communication skills.

Following is the list of prominent roles and responsibilities of SDET:

To understand the requirements of a client and design high-level test scenarios.
To make an automation framework for integration testing.
To make a UI automation testing framework for application testing.
To write the unit testing code and review the unit testing results of other developers.
To optimize the code and do performance testing of the code.
To involve in the application security testing and enhancements.
To get involved in release management.
Coordinate with the development and testing team regarding customer requirements.
Always work to improve the product in faster development, minimum defects, faster testing cycles, and quick results with a robust automation framework.
To provide the clients with improved performance and security.

3) What is the skill set required for an SDET role?

Following is a list of skills that are required for an SDET role:

Quality Assurance & Testing Knowledge

A candidate looking for the SDET role must know the Testing Methodologies and life cycle.
Good knowledge of quality assurance and quality concepts.
Good knowledge of test cases and bug reporting
Must be familiar with the tools like test management and bug reporting tools.

Coding & Programming Knowledge

Good knowledge of programming languages such as Java, Python, or .Net. Must be aware of object-oriented programming aspects like classes and objects.
Good knowledge of unit testing frameworks like Junit and TestNG is required.
He must have a good knowledge of automation tools such as Selenium or other paid tools.
He must have a good knowledge of performance testing tools such as Jmeter.
He must have a good knowledge of Cloud computing-related technologies and services such as Google Cloud, AWS & Azure.
He must have a good knowledge of Agile methodologies and version control systems like Git.
He must have a good knowledge of API testing tools such as PostMan, Rest-assured, or SoapUI.

Other Required Skills

The candidate must have good research and analysis skills.
Capable of providing multiple solutions for a given problem.
He must have a positive and enthusiastic approach because SDET has to deal with two roles, so he should always be in a positive and calm mode while working.
He must have good communication skills, both verbal and written.
Good time management skills and must be a good team player.

4) What is Adhoc Testing? How can we define ad-hoc testing in the current IT industry?

Ad-hoc testing is entirely different from formal testing. It is an informal testing type in which testers do not follow any documents, test design techniques, and randomly test the applications. This testing is mainly performed by the testers who have deep knowledge about the application under test. In this testing, testers randomly test the application without using any test cases or any business requirement document.

If we talk about the current IT industry, Ad hoc testing is one of the most popular testing nowadays. We have to perform this testing when some ad hoc requirements come from the client. In this technique, the developers have to develop test cases immediately and provide accurate deliverables in a minimal time. This is rapid testing, so documentation or planning is not always possible, but some organizations have dedicated teams and specific tools for tracking and delivering this kind of task.

5) What are the key differences between a Software Development Engineer in Test (SDET) and a Manual Tester?

In a software & IT organization, a manual tester is a person who performs software testing to find bugs and errors in the application's code. The tester also has to examine several software features without knowing the entire software development process. On the other hand, a Software Development Engineer in Test or SDET is responsible for doing testing and has a good knowledge of the software development process.

Following is a list of key differences between an SDET and a manual tester:

Software Development Engineer in Test (SDET)	Manual Tester
SDET stands for "Software Development Engineer in Test," It is a tester with excellent knowledge of programming languages and coding. In other words, we can say that an SDET is a tester who is also a coder.	A manual tester is an employee designated to test software or systems after the development teams have developed them.
As SDETs have a good knowledge of coding and testing, they are involved in every stage of the software development process.	Testers have only knowledge of testing software or systems, so they are involved in only the testing stage of the software development process.
An SDET professional has good knowledge in design, implementation, and testing.	A manual tester does not know software's design and implementation. They are only involved in executing test cases.
SDET professionals can develop test automation tools.	Manual testers are not required to develop test automation tools or frameworks.
The scope for SDET testing is quite broad as they focus on multiple testing types and techniques- for example, security, functional, non-functional testing, etc.	The testing scope for manual testers is much narrow as they have to focus only on the functionality aspect of the application.
The SDET professionals also check the performance of the software.	The manual testers are only responsible for testing bugs in the software. They don't care about performance of the software.
SDET professionals are well versed in software requirements and other related topics.	The manual testers have a limited understanding of software requirements.
The SDETs professionals are concerned with white and black box testing.	The manual professionals are concerned with black-box testing.
The salary of SDET professionals is generally higher than that of manual testers.	The salary of manual testers is lower compared of SDET professionals.

6) What is the code inspection in the context of software testing? What are the steps involved in code inspection?

Code inspection is a type of static testing in which the testers inspect software code and find bugs. It simplifies the initial error detection procedure, lowers the defect multiplication ratio, and avoids subsequent stage error detection. The code inspection is a part of the application evaluation procedure.

Following is the list of critical steps involved in code inspection:

The main members of the inspection team are the Moderator, Reader, Recorder, and Author.
The main task of the inspection team is to receive related documents, prepare the inspection meeting, and coordinate with the inspection team members.
If any inspection team member is unfamiliar with the project, the author provides him with an overview of its code.
After this step, each inspection team conducts a code inspection using inspection checklists.
After the code inspection is completed, a meeting with all team members is conducted to discuss the inspected code.

7) What is the main difference between Severity and Priority?

Severity specifies the effect of a specific defect or error in a bug on a customer's business. It is used to measure the degree of impact the issue will have on the system. Severity can be categorized into three types, critical, major, and minor.

Priority specifies how important it is to fix the bug. It is assigned according to the degree of potential severity. The developers assign priority to different defects to be resolved in a definite order. So, we can say that priority is an order in which the bug is addressed. It can be categorized into three types, high, medium, and low.

8) What are the advantages of code inspection in software testing?

Following is the list of main advantages of code inspection in software testing:

Code Inspection is the best way to find bugs and flaws in software code.
It can enhance the overall quality of the software.
It can be used to mark any process improvement.
It can effectively find and remove functional defects.
It is also a good way to correct the prior flaws.

9) What are the critical differences between exploratory and Ad hoc testing?

Following is the list of key differences between exploratory testing and Ad hoc testing:

Exploratory Testing	Ad hoc Testing
In exploratory testing, the testers do not know the requirements and carry out the test based on exploring the functionalities of an application.	Ad hoc testing comes under the category of informal testing, and it is executed without any prior documentation or planning, or adherence to any specific test design technique.
Exploratory testing provides the freedom of ad hoc testing with more advantages than somewhat formal testing.	Ad-hoc testing is an informal, free-form software testing method that can be performed without an intense knowledge of the test subject.
Domain experts mainly execute this testing.	This testing is executed when testers are experts and have good knowledge about the Application Under Test (AUT). There are no expected results or business requirement documents, or test cases.
This testing facilitates the testers to ask questions about what the product can do and how to sort out appropriate testing.	Ad-hoc testing is entirely different from structured testing, and that's why it doesn't have any rules, goals, documented plans, or targets. The efficiency of such kind of testing entirely depends on the experience level of the tester.
This testing is structured enough to provide reliable results, and it can effectively locate new difficulties in test cases.	This testing is difficult to manage, and often due to lack of documentation, any discovered bugs will be difficult to reproduce as well.

10) What do you understand by Alpha and Beta Testing?

Alpha Testing: Alpha Testing is a type of testing conducted by testers to identify the presence of any bugs before the release of the application into the live environment.

Beta Testing: Beta Testing is a type of testing conducted by the end-users in the real-world environment who happen to be the actual users of the application. In other words, we can say that the application is released in beta testing, and the application users are the actual tester.

11) What is the Fuzz Testing?

Fuzz Testing is a testing process where a tester identifies the security loopholes and coding errors and the locating hack prone software bugs. In this testing, the tester injects a large amount of random, incorrect, and accidental data into the system to make it crash and then identify if anything breaks into the system.

12) What do you understand by Risk-Based Testing?

Risk-based testing specifies the testing of the functionalities of a product according to the priority of the deliverables. In this testing, the criteria of business requirements are taken as the yardstick, which helps determine the priority of all functionalities of a product. The high-priority functionalities with the highest business impact are tested first, followed by the medium and low priority functionalities. This testing is mainly used when there is a lack of time for testing all the functionalities.

13) How can you decide what product is ready to ship?

This is mainly the job of the organization's upper management, which takes a call when a product is ready to ship. The testing team is devoted to finding and fixing all the bugs within the application. When a testing team is confident that all bugs have been identified, documented, and resolved, they inform upper management. SDET must make sure that management has all the necessary information to make a correct decision.

14) What is the crucial difference between Quality Assurance and Quality Control?

The main difference between Quality Assurance and Quality Control can be specified as that Quality Assurance mainly emphasizes the process of quality. On the other hand, Quality Control mainly emphasizes the quality of the output.

Quality Assurance: It is a preventive strategy that mainly focuses on planning, documenting, and agreeing upon a definite set of guidelines necessary for ensuring quality. It is mainly used at the beginning of a project, and its main objective is to restrict defects from entering into the solution in the first place.

Quality Control: Quality Control, on the other hand, is a reactive strategy that mainly focuses on all activities which determine the quality of the delivered solutions. It uses many specified quality standards to provide quality output.

15) What do you understand by a bug report in software testing?

In software testing, a bug report is a detailed report that specifies what is incorrect in the application/software or on a website that needs to be fixed. This bug report consists of a request and details for addressing each issue and a list of causes or noticed faults to precisely pinpoint what is perceived as wrong.

In other words, we can say that bug reports are a technique to inform developers about parts of their written code that are not working as expected or designed. It also facilitates developers to see which parts of their software need to be improved. Testers create bug reports to provide feedback to the developers about the faults in their code. Without this report, it is tough for developers to find bugs in their written code. The software testers can make this process considerably easier by providing high-quality bug reports consisting of all information a developer might require to find out the problem.

16) What are the qualities of a good bug report?

A good bug report must have the following qualities:

A good bug report must provide a descriptive summary of the bug found within the code.
It should specify every problem within the code and provide clear, precise, and relevant information.
It should provide explained information on the real and expected behavior of the bug.
It should provide environment information and include the steps for reproducing the bug.

17) What are the most prominent elements of a bug report in software testing?

Following is the list of most essential elements of a bug report in software testing:

Title: Title is the first and most crucial element of a bug report. A good title is simple and small, and it should provide a detailed description of the bug to the developer and the bug's category. In this app component, the bug happened, i.e., Cart, UI, etc., and the activity or conditions in which the bug occurred. A clear title is essential because it makes things easier for the developers, and they can find the report and distinguish the duplicate reports easily.

Description: It provides a concise summary of the bug and specifies how and when it occurred. This section contains additional information from the title, such as the frequency with which the bug happens if it is an intermittent error and the situations that appear to trigger it. It also contains information about how the bug is impacting the application.

Environment: Environment and surroundings play an essential role in the behavior of an application. This section provides all the information about the app's environment setup and settings.

Repro Steps: It specifies the essential things for reproducing the bug. These steps should be short, easy, and accessible to anybody. The main goal of this step is to facilitate developers and make them able to reproduce the error on their end to figure out what's wrong. A bug report without repro steps is useless and a waste of time for developers that could be better spent resolving more complete reports. A tester must follow the rules of this step.

Severity and Priority: The situation determines the severity and priority of an issue. The severity levels and definitions may vary among program developers, testers, and end-users. It can be categorized in the following way:

Critical/Blocker: This category specifies the faults that render the application useless or result in significant data loss.
High: It is called high when a bug affects a significant feature, and we don't have any solution, or the provided remedy is highly complicated.
Medium: It is called medium when the bug affects a minor or significant feature, but there is a simple enough fix to avoid significant discomfort.
Low: This is used to specify defects that may impact less on the user experience, such as minor visual bugs, etc.

Actual Result: It specifies the actual result or output that the user or tester sees.

Expected Result: It specifies the anticipated or planned consequence or result or output.

Attachments: Attachments are provided to assist the developers in finding the problem faster. For example, a screenshot of the problem can explain a lot and may be very useful, especially when the problem is visual. Besides this, logs and other handy attachments guide the developer.

Contact Details: It provides additional information regarding the errors or issues. For example, an email address where the users can contact or submit if they find any bug. You can also provide alternative communication routes if the users find it difficult to react to emails. It can enhance efficiency.

18) What are some software testing tools used in the industry? Explain their key features also.

Following is a list of some of the software testing tools used in the industry:

TestRail: TestRail is a web-based scalable and flexible test case management system. You can set up its cloud-based/SaaS solution in minutes or install your own server on TestRail.

Testpad: Testpad is another manual testing tool. It is a more straightforward and accessible tool and mainly emphasizes pragmatism over method. It uses checklist-inspired test plans that can be modified to a broad range of approaches, including exploratory testing, the manual side of Agile, syntax-highlighted BDD, and even traditional test case management, rather than handling cases one at a time.

PractiTest: It is a complete test management solution that provides comprehensive visibility into the testing process. It also provides a better, broader understanding of testing outcomes by serving as a common meeting ground for all QA stakeholders.

Xray: Xray is a full-featured testing tool that exists inside Jira and works flawlessly with it. It is mainly used to help businesses improve the quality of their products through efficient and practical testing.

TestMonitor: TestMonitor is a testing tool that provides end-to-end test management capabilities. It is a straightforward and intuitive testing tool that can help you adopt corporate software, need QA, produce a quality app, or help in your test project.

SpiraTest: It is a cutting-edge test management solution for large and small teams. It facilitates testers to handle requirements, plans, tests, issues, tasks, and code in a unified environment. It is ready to use right out of the box and adapts to your needs, methodology, workflows, and toolchain. It uses the agile method of working.

19) What are the main objectives of alpha testing?

Alpha testing is a type of software testing used before the product's release. It is mainly used to determine the issues before releasing a product to the end-users or the general public. It is called alpha testing, done early in the software development process, near the end. This software testing is mainly done by software developers or quality assurance staff, and it is the final level of testing before the release of the software into the real world.

Following is the list of main objectives of alpha testing:

The main aim of alpha testing is to improve the software product by finding the missed bugs in previous tests.
It is also used to improve the software product by identifying and addressing the missed flaws during previous tests.
This testing brings the customers into the development process as early as possible.
Alpha testing provides a better understanding of the software's reliability during the early phases of software development.

20) What are the different types of beta testing?

Beta testing is a type of testing where genuine software application users test the application in a real environment. This is a type of user acceptance testing. A small number of product end-users are given a beta version of the program to receive input on product quality. It reduces the chances of a product failing and improves its quality by allowing customers to validate it.

Following is a list of the different types of beta testing:

Traditional Beta testing: This type of testing distributes the product to the target market and collects all relevant data. It provides some helpful information that can be used to improve the product.

Technical Beta Testing: In this type of testing, a product is delivered to a group of employees of a company, and feedback/data is collected from the employees.

Focused Beta Testing: In this type of testing, a software product is distributed to the public to collect input on the software's most essential features.

Public Beta Testing: In this type of testing, the product is made available to the general public via web channels, and data is collected from anyone. After receiving the data, improvements can be made to the product according to the customer input. For example, before its official release, Microsoft used all Beta Tests for its operating system Windows 8.

Post-release Beta Testing: This testing is used when the software product is launched to the market. After that, data is collected to improve the product for future releases.

21) What is the key difference between Code Walkthrough and Code Inspection?

The key difference between Code Walkthrough and Code Inspection is that the Code Walkthrough is an informal review that comes under an informal meeting. Here, the author describes the work product to his supervisor or peers to receive feedback. It is mainly used to check the validity of the product, and it is often considered a static method of quality assurance.

On the other hand, the Code Inspection is a type of formal review that comes under a product's compliance with specific requirements and standards. The project team initiates it, involves fixed meetings, and compares the product with specific documents and code. It includes systematic and structured testing, which improves a software product's availability, maintainability, and reliability.

22) What are the key differences between Alpha and Beta testing?

The following table consists of the key differences between Alpha and Beta testing:

Alpha testing	Beta testing
Alpha testing consists of both white box and black-box testing.	Beta testing consists of only black-box testing.
Alpha testing is frequently /mainly done by testers who are full-time employees of the company.	Beta testing is mainly done by clients who are not company employees.
Alpha testing does not follow any reliability or security testing.	Beta testing mainly checks the application's reliability, security, and robustness.
Alpha testing takes place on the developer's premises.	Beta testing takes place on the product's end-users.
It is the responsibility of the alpha testing to verify that the product is of high quality before moving on to beta testing.	In Beta testing, the users mainly focus on the product's quality. They also gather user feedback and ensure that the product is ready for real-world use.
Alpha testing is a lengthy process, and its execution cycle is very lengthy and time-consuming.	Beta testing is not a lengthy process, and it requires a small amount of time for testing applications.
Alpha testing requires using a lab or a testing environment to test applications or code.	Beta testing does not require a testing environment, setting, or laboratory.

23) How can we test the text boxes without changing their backgrounds?

We can test the text boxes without changing their backgrounds if we don't pass any following type of following data:

Alphanumeric Values
Text Format
Special Characters
Size of the Text Field
Minimum/Maximum Characters etc.

24) Which specific format of the bug report, a tester can be demanded?

If a tester is asked for a specific format of the bug report, then he can follow a conventional approach to provide the report. The bug report must contain the following elements:

Bug Summary
Reproduce Steps
Expected and Current Behavior of One Specific Bug

25) What would a tester do if there is no proper testing documentation available?

If any situation where proper documentation is not available for test cases and the tester still has to execute the test case, in such a situation, the tester can follow some earlier mail provided by the client, which describes all the requirements clearly. He can also refer to the screenshots where the details of the changes are mentioned.