Key Types of Software Testing Every Tester Must Know

Software testing is the backbone as far as quality assurance in software development is concerned. Its important task is to verify that the software not only works as designed but is also reliable and meets user expectations. According to the US research software testing market, it was estimated valued at USD 2.4 billion in 2024.

In the industry, discussions about software testing and its various types are common, but Alphabin has gone beyond the usual discussion. After years of experience and constant improvement in our approach, we have crafted a proper form of software testing that brings pure and effective techniques with real-world impact.

The purpose of this blog is to help you understand the software testing types needed to build quality software. While white box testing reviews the inside of the code and black box testing evaluates the functionality of this software from the user’s perspective, grey box testing falls somewhere in between, and this article covers what makes each individual software as great as it is today.

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What is Software Testing?

Software testing checks a software application or system to find and fix issues before it is released. The main goal is to ensure the software works as expected, meets requirements, and is reliable and functional. For that goal, the application runs into specific conditions.

Why is Software Testing Important?

Software testing is important for several reasons:

• Bug Detection: The availability of a system with a minimal number of bugs in the initial stage of development is cheap relative to a system with numerous bugs at the final stage.
• Ensure Functionality: Testing is carried out specifically to guarantee that the software fulfills its intended functional specifications.
• Improves Security: Security testing identifies the areas that may lead to the vulnerability that can be exploited for malign intent.
• Enhances Performance: Testing for performance helps to gain knowledge of areas of possible slowdown and to check how the software benefits from it.
• Boosts User Satisfaction: In testing, the customer's experience and trust is enhanced through defect-free and easy-to-use software.
• Compliance Assurance: There are countless industries that face strict regulatory policies as per which the product has to pass extensive testing before it is sold out.

Different Types of Software Testing

There are mainly three types of software testing based on the visibility of the internal workings of the system that are White Box, Black Box, and Gray Box. Each of them is oriented to different components of the testing process.

1. White Box Testing: White box testing, or glass box, is a type of software testing of the internal structure, logic, and code of the software. This type of testing can be done by both developers and testers who have a good working knowledge of the application’s source code.
2. Black Box Testing: Black box testing is the testing of an application without internal knowledge of the code or logic of the application. Here a tester will spend a lot of time on inputs and outputs and make sure that the software behaves the way it’s supposed to. It’s great because it mimics how an end user interacts with the application, making it great for validating user experience.
3. Gray Box Testing: Gray box testing is created by combining the techniques of white box and black box testing. With partial knowledge of the internal structure of the application, testers can work with a user-centric approach and create more informed test cases.

White Box Testing

Here are the testing categories under white box testing:

1. Unit Testing

Unit testing tests individual components or unit codes (e.g., functions, methods, etc.). It ensures each component is working as intended in isolation. 

For example, testing a login function to ensure it handles input correctly.

2. Integration Testing

Integration testing verifies that different components or modules integrate and work as one. The main goal is to determine if any issues arise when multiple components work together. 

For example, testing if a shopping cart module integrates properly with a payment gateway.

3. Code Coverage Testing

Code coverage testing ensures all lines of code are executed during testing, leaving no part of the application unchecked. Cover all possible paths in the code to ensure every scenario is tested. 

For example, if a function contains an if-else statement but only the if condition is tested, code coverage testing will highlight the untested else branch.

4. Path Testing

When path testing is used, it is a guarantee that every possibility of the program is tested once. It is based on the control flow of a program. 

For example, for a program with a loop and a conditional branch, path testing ensures that both the loop and the branches are tested.

5. Loop Testing

Loop testing completely focuses on the validity of the loop constructs; it is one of the parts of control structure testing (path testing, data validation testing, and condition testing). 

For example, a loop that iterates through an array must be tested for proper handling of array bounds.

6. Control Flow Testing

Control flow testing techniques focus on the stream through which the instructions or statements of a program are executed. Testers use the control structure (loops and conditions) of the program to develop test cases. A specific part of the program is selected, and the structure of further test cases is determined. 

For example, for an if-else structure, control flow testing ensures both the if and else blocks are executed.

7. Data Flow Testing

Data flow testing examines the flow of data in a program. It focuses on the point where variables are defined and used and aims to identify and eliminate potential anomalies that could disrupt the flow of data, leading to program malfunction and incorrect outputs. 

For example, it is testing a program that assigns values to a variable but forgets to use it or improperly overwrites it.

Black Box Testing

Black boxes are classified into two parts, functionality and non-functionality of communities. This gives an idea of ​​where to start. Let's start with functionality first.

Functional Testing

Functional testing is a form of software testing that attempts to verify whether the final product functions as desired and whether it is useful in meeting certain business requirements. The types of functionality testing are as follows:

1. Smoke Testing

Smoke testing can be considered a subset of functional testing, where the idea is to ensure that critical features or functionality of an application are working.

For example, after a new build of the shopping app is deployed, the testers ensure that the app will launch and the homepage and log-in page will be functional. These basic tests ensure that all is okay for further testing.

2. Accessibility Testing

This test ensures that the software application may be accessed by disabled people out there who have either visual, hearing, or cognitive impairment. 

For example, testing a banking app to ensure that visually impaired users can navigate the app using screen readers like NVDA or VoiceOver and that it supports high-contrast mode for colorblind users.

3. API Testing

It is a software test that analyzes an application programming interface (API) to verify that it meets its expected functionality, security, performance, and reliability. 

For example, validate a weather app’s API by sending requests for a city’s weather data to the API and confirming if the API is returning the correct temperature, humidity, and wind information in JSON format.

4. Regression Testing

In this kind of regression testing, all the changes are intended to guarantee that the code modification is not influenced by the existing functionality. When there is a bug in the system and it is corrected, regression testing is concerned with if and only if that part is working or not. 

For example, if a bug is fixed for the login feature, then we test for regression to ensure the fix doesn’t break the password recovery and signup text.

5. Security Testing

Security testing is an essential part of software testing. It is used to discover the vulnerabilities, risks, or threats in software applications and prevent attacks from the attackers. 

For example, e-commerce site testing to check for proper payment processing such as encrypting credit card info and protection against SQL injection attacks.

6. UI/UX Testing

UI/UX testing is majorly centered on the looks and feel of the interface as witnessed by a user. It makes certain that its design side (UI – user interface) is appropriate and so is the experience side (UX—user experience). 

For example, buttons in a food delivery app should be intuitively placed and the color scheme shouldn’t distract the eyes for a smooth and visually pleasing user experience.

7. End-to-End Testing

End-to-end testing is a types of software testing approach that aims to provide an overall quality check of the effectiveness and capability of an application from start to end. 

For example, simulating an entire order process through an online store, from adding an item to the cart, purchasing an item, making a payment, and receiving a confirmation email.

8. User Acceptance Testing (UAT)

User acceptance testing (UAT) is the final testing process in which actual users or stakeholders use the software to confirm whether it meets the defined requirements or not. It provides the final check to validate accomplishments as the software is ready for release and works as intended. 

For example, before rolling out new HR management software, a group of end users tests it to make sure it meets their requirements for payroll processing and employee attendance tracking.

9. Beta Testing

In this testing, a limited number of users (outside the development team) will use the application and give feedback on that application so that issues can be identified and addressed before the release of the application. 

For example, releasing a beta version of a new messaging app to a set of users and getting feedback to improve performance and features, as well as fixing bugs before a final release of the app.

10. Integration Testing - APIs

API integration tests are just to make sure the API endpoints will work correctly with other parts of the system or with our external services. Working with the API is helping the API run properly, give proper data, or send proper data. 

For example, testing a travel booking platform with a flight booking API and hotel reservation API integration to make sure that the hotel reservation API works nicely with the flight booking API to book travel packages.

11. Sanity Testing

The sanity test is just a quick check to make sure we haven't broken anything with the latest changes or improvements being made to the software. It tests specific areas of the software to verify that the core functionality is still working as before. 

For example, after fixing a crash with the search bar of a library app, the testers then do some sanity testing to make sure the search bar works and doesn’t crash the app, as it should.

Non-Functional Testing

Non-functional testing focuses on testing the quality of a software application that is related to performance, compatibility, usability, and scalability. It tests all the system’s parts and works well on all different conditions and not just specific features or functions.

1. Performance Testing

It is the type of software testing that tests the way a system behaves under certain conditions. This is known as performance testing. It measures how fast it is, whether it is responsive enough and whether it is stable when given a certain workload to work with. 

For example, checking if a music streaming app can buffer or crash during the running of the app under various conditions with at least 100,000 simultaneous users.

2. Compatibility Testing

Compatibility testing is software testing in which software is tested to check if it works as expected in other environments. This includes many things, such as hardware, operating system, browser, device, or network conditions. 

For example, a perfect gaming app that will work flawlessly on Android, iOS, and a variety of versions of each operating system with devices of varied screen sizes.

3. Load Testing

It is a testing type that ensures that the application can handle a large number of users working at the same time without any delay. 

For example, examining how an online learning platform might perform under heavy traffic by simulating 10,000 users accessing the online learning platform at the same time.

4. Stress Testing

Stress testing is a type of performance testing that identifies the breaking point of an application and ensures that software applications can handle even unexpectedly high loads without crashing. 

For example, simulate 1 million users at a point of ticket sale for a concert and see if the system crashes under extreme conditions.

5. Usability Testing

Usability testing validates how easy and user-friendly a software application is for people to use. It analyzes whether the application is simple, intuitive, and meets the user's needs. 

For example, watch a group of users trying to figure out how to create profiles on a new social networking site and see if they get confused or spend too much time on it.

6. Scalability Testing

Scalability testing checks whether a software application can support more users, data, or tasks when the demand increases. It enables the system to be autoscaled up or down smoothly with no performance issues. 

For example, testing a food delivery app and gradually increasing the number of orders in parallel by order of 500 to 50,000 times to see how the app responds.

Gray Box Testing

Now we know about white boxes and black boxes. So now gray box, which is a partial mixup of white box or black box.

1. Database Testing

Database testing is software testing by which the functionality, accuracy, efficiency, compatibility, security, and integrity of a database system is verified. It ensures that any operations between our application and the database must be seen by the user and it also ensures data integrity; data must be stored, retrieved, and processed properly. 

For example, verifying that a user's profile update in an app correctly reflects changes in the database, such as name and email.

2. Fault Injection Testing

Fault injection testing is a method of testing in which faults or errors are deliberately introduced into a system to test how the system reacts to failures. It identifies weak points in the system's error-control and recovery processes to keep the entire system reliable and robust. 

For example, they can mimic a network outage in a video streaming service, to check if a replay occurs when the connection is back.

3. Session-Based Testing

As a form of structured testing, session-based testing is employed in exploratory testing. These are carried out by the testers in a stipulated time and without any interruption. Finally, the findings are evaluated, and issues or learnings in the component are also noted. 

For example, for 60 minutes, implement/practice the login feature and login attempts with valid, invalid, and edge-case credentials and write in the specification.

4. Regression Testing - Gray Box

In a gray box context, regression testing is used for testing whether or not changes made to the system, such as bug fixes or updates, have had a detrimental effect on existing system functionality. Regression tests become optimized when one has partial knowledge of the system. 

For example, introducing new payment options in the application and ensuring that all the default options like credit cards, PayPal, etc. continue to work as well.

5. Penetration Testing - Gray Box

Grey box penetration testing is a testing process where one knows only limited information about the networks and other infrastructures that are being tested. With this information, the tester is in a position to report the vulnerability while applying their experience. 

For example, using a normal account to attempt to view the restricted areas of a website.

Which Software Testing Methodology is Best for Your Project?

You have many testing methodologies to choose from, and based on your project, we can conclude which testing methodology is suitable for your project. You want to create a fully customized strategy to achieve the goals of your application and understand the different testing approaches, including automated testing, to achieve success.

This guide can help you identify some of the methods that can be useful in meeting your testing needs. You should know that software testing is not just about finding defects but about creating a good and stable product to satisfy your customers. Choosing the proper testing approach will ensure that your program will run optimally in multiple environments, enough that it will meet the necessary specifications and be compliant with industry requirements.

To increase the efficiency and effectiveness of testing, use a variety of testing tools that can greatly improve testing. These platforms are designed to provide new opportunities in order to minimize testing and development manual work and increase flexibility in the course of the development life cycle.

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Conclusion

Software testing involves testing all the internal logic of the application and user interactions to ensure that the software is reliable, functional, and secure before release. It removes bugs, enhances performance, improves user satisfaction, and secures compliance. Through a combination of white, black, and gray box testing, teams can develop robust, user-focused software. Choosing between manual vs. automated testing is critical, as the right approach optimizes quality and speed in complex projects.

Alphabin utilizes the most advanced automation testing to speed up software testing, improve reliability, and use resources more efficiently. Organizations can gain higher testing efficiency, quicker time to market, and more reliable products that fulfill customer expectations and industry standards using automation experts.