For enquiries call:



HomeBlogSoftware TestingWhat is Software Testing? [Types, Process and Models]

What is Software Testing? [Types, Process and Models]

05th Sep, 2023
view count loader
Read it in
12 Mins
In this article
    What is Software Testing? [Types, Process and Models]

    We live in a world where software is integral to our daily lives. We have all experienced situations where software failed to perform as expected. Poor quality software can result in significant financial impact and brand damage for organizations. Consumers are picky about the software they choose.

    • According to Statista, more than a third of smartphone users delete an app when they encounter a software bug,  
    • According to Localytics, 21% of users abandon an app after one use.  

    Today's digital users are more demanding than ever. As a result of growing consumer demands, organizations invest in software testing to provide high-quality software for their customers. This article will look at software testing, the fundamentals of software testing, and some tips on getting started.  

    What is Software Testing?

    Software development is a complex and multifaceted activity. Perfect software is a myth. Developing software can be challenging, regardless of how cautious or skilled you are. The software will inevitably have bugs. 

    • How do you know your software works before rolling it out to production? 
    • How do you know if there are any risks? 
    • How do you know that the software is of acceptable quality and meets user requirements?  

    Enter software testing; Testing is a search for the truth.  

    Software Testing is a service for software development. Software testing determines if the software does what it is supposed to do and meets the customer's expectations. Testing helps you to quantify the risk in an untested piece of software. The common misconception is that testing is merely executing the software and checking the results. Testing software goes beyond comparing results with expectations. To test, you must explore. The definition of software testing I like the best is:  

    Testing is the process of evaluating a product by learning about it through experiencing, exploring, and experimenting, which includes, to some degree: questioning, study, modeling, observation, inference, etc. A test is an instance of testing.  James Bach and Micheal Bolton 

    Software testing = Verification (whether the system meets specified requirements) + validation (whether the system will meet user and other stakeholder needs) 

    Testing = Checking (does the software behave as intended under conditions it's supposed to handle?)  + Exploring  (are there any other risks?)  Elizabeth Hendrickson 

    What is the Objective of Software Testing?

    Software Testing has various objectives. The ultimate goal of software testing is to deliver high-quality software. There is a misconception that testing is solely about finding bugs and defects.  Software testing typically includes the following objectives [ISTQB]:

    1. To Prevent defects: Testers achieve this by testing the code as well as other software artifacts like the requirements, design, code, documentation, etc.
    2. Verifying that all specified requirements and compliances have been met.
    3. Validating if the Software works as per the user's expectations.
    4. To build confidence in the level of quality.
    5. Finding defects to reduce the risk of delivering poor software quality.
    6. Testers provide information to stakeholders for decision-making, particularly regarding the quality of the product. Get the right foundation with our courses for Software Testing.

    Importance of Software Testing

    Software testing saves costs. Bugs are expensive. Buggy software can lead to loss of money, time, business reputation, or even injury or death in the case of safety-critical software. Look at some infamous software bugs to understand how expensive they are. 

    • The US launched Mariner 1 into space and attempted to send it to Venus for the first time in 1962. The rocket got off course due to a software bug costing millions of dollars.  
    • The Y2K bug (Millenium bug): The computers could not distinguish between the years 1900 and 2000. Both 1900 and 2000 were represented as 00 instead of 1900 and 2000.  Computer systems worldwide were upgraded, spending billions of dollars. 
    • In early 2010, Multidata's software-controlled radiation therapy system overdosed dozens of patients and killed 9 of them. 

    The earlier you find bugs, the better. The cost of fixing defects in software increases exponentially with time in the software development lifecycle. The later the bug is found, the more expensive it is to fix. According to Boehm's Curve, fixing the same bugs earlier in the curve is cheaper. As a result, organizations today involve testers as early as possible during the development process.

    Boehms Curve

    Reputation is everything in business. Users will leave a bad review, stop using the app, and find alternatives if they have a terrible experience. Software testing helps uncover risks and bugs that hamper customer experience. Testing software accelerates the development of high-quality software.  Furthermore, it helps build a good reputation by gaining customers' trust, loyalty, and satisfaction.

    The History of Software Testing

    From ancient human civilizations, society has strived for quality. Quality assurance has a long history.

    • While constructing Ancient Indian Temples quality of construction materials was checked. Before building the original temples, smaller temples were built as prototypes to test the design and other factors.
    • In the Middle Ages, Various trades, such as blacksmithing, were regulated by guilds to guarantee quality. Several guild masters would inspect the goods to ensure a high-quality standard.
    • Modern quality assurance began with the Industrial Revolution. As factories grew, an inspection of products became more important.
    • Harvard University's computer scientists reported the first computer bug in 1947 when they caught a moth inside the Mark II computer. As Dr. Grace Hopper put it, the moth was the "bug" that caused the error, and the removal of the bug was known as "debugging." Several also claim that Thomas Edison coined the term "bug" for the first time in 1878. Edison supposedly wrote a letter to his associate in which he used the term “bug” for the first time.
    • Alan Turing wrote his first article about testing a program in 1949, and later in 1950, in the article “Turing test.”
    •  In 1951, Joseph Juran, for the first time, marked the importance of software quality assurance in his book “Quality control handbook.”
    • The primary method of testing software in the early days was debugging. Charles L. Baker distinguished program testing from debugging in 1957, marking the beginning of the modern history of software testing.
    • Gerald M. Weinberg formed the first testing team for Project Mercury in 1958 - the first American human spaceflight program.
    • Glenford J Myers, in 1979 distinguished software testing from debugging in the book “Art of Software Testing.”
    • The early 2000s saw the rise of Agile and that test-driven development (TDD) and behavior-driven development (BDD).
    • Selenium was developed by Jason Huggins in 2004. In 2008, the DevOps movement began to gain traction.

    Since then, the testing landscape has constantly changed.

    Software Testing Fundamentals 

    Software testing is classified based on various aspects. Let's look at some of them. Even though some of the classifications below are debated and criticized by experts, the following remain popular.

    A. Manual software Testing and Automated software testing  

    Manual software testing involves testing the software manually, i.e., without using any automation tool or script.  Test automation, or automated software testing, refers to writing scripts and using an automation tool to run the test. Automation vs. manual testing comes down to who runs the tests. The human tester performs manual testing. Automation testing is done by the tool.  

    B. Test Levels  

    In Software testing, test levels are groups of activities organized and managed together. Software testing takes place at different stages of the software development life cycle. Software testing is a continuous process, not something that occurs at the end.  

    The four levels of software testing are as follows: 

    1. Unit/Component Testing - focuses on separately testable components. It is often done in isolation from the rest of the system. Typically, unit tests are very low-level and close to the source codeThe objective is to test whether an application's units (e.g., classes, functions) meet its requirements. Typically unit tests are performed by the developers. 
    2. Integration Testing - This type of testing focuses on the interactions between components or systems. Integration testing determines whether different modules or services used in your application work well together. Both testers as well as developers, can perform integration tests. 
    3. System Testing(End-to-End testing) - System testing examines the system's functionality overall. Its objective is to ensure that the system meets its requirements and operates as intended. Software testers usually carry out this type of testing. 
    4. Acceptance Testing - The objective of acceptance testing is to assess whether the system is ready for deployment and use by the customer. So that the customers can develop confidence that the system can meet their needs, acceptance testing is often performed by customers or stakeholders or by their testing teams. 

    C. Testing Types  

    A test type refers to a set of test activities designed to assess specific characteristics of a software system. The following are the types of testing in software engineering:    

    1. Functional and Non Functional testing  

    • Functional testing - Testing an application's functionality against a set of requirements.  
    • Non-functional testing -  examines different factors that functional testing doesn’t cover. The purpose of non-functional testing is to evaluate the non-functional quality attributes of software, such as Usability, Maintainability, Efficiency, Reliability, and Portability. To comprehend all the '-ilities', refer to the ISO standard (ISO/IEC 9126) 

    2. Whitebox testing, Blackbox testing  

    Black box testing aims to test software from a behavioral perspective without knowing the internal code implementation. The primary source of black box testing is the customer's specifications (requirements) 

    Black Box

    Below are some of the most popular Blackbox testing techniques-  

    • Equivalence partitioning  
    • Boundary value analysis 
    • Decision table 
    • State transitions 
    • Use case testing 
    • Error Guessing 
    • Checklists 

    White-box testing is concerned with testing a system's internal architecture or implementation. A white box technique examines the system's internal logic like code, architecture, workflows, dataflows, etc. White box testing demands knowledge about the source code.  

    Below are some of the most popular Whitebox testing techniques-  

    • Statement Coverage   
    • Branch Coverage  
    • Path Coverage 
    • Control flow testing 
    • Data flow testing 

    Spend some time learning about the testing techniques described in the above sections. 

    Today, the distinction between white-box and black-box testing has blurred and is becoming less relevant. Tests derived from the tester’s skill and intuition and their experience with similar applications and technologies have proven more effective. The exploratory testing approach to software testing involves learning, designing, and executing tests simultaneously. Exploratory testing is something you should learn and practice. 

    Pre-requisites to be a Software Tester  

    Getting started with testing may seem intimidating to newbies. A growth mindset and a passion for testing are all you need to succeed.  The key to excelling in software testing is to get the right training, education, and fundamentals.  

    A tester needs both technical and soft skills to be effective. Testers' most sought-after soft skills are communication, analytical skills, organization, time management, Detailed Orientation, Curiosity, Creativity, Negotiation skills, and the ability to think critically. Regarding technical skills, testers need programming, familiarity with automated software testing tools ls, exploratory testing, etc. Some roles require specialized skills, such as performance and security testing, Accessibility testing, usability testing, etc.   

    Software testers don't need programming experience to get started. Learning to code, however, can enhance your productivity. Developing programming skills is the first step toward a career in test automation. Test automation eases your day-to-day tasks, such as generating test data and performing repetitive regression tests. 

    A tester may take on a wide range of responsibilities, either within or outside the testing function. Testers may eventually move into leadership roles like managers or become test architects. Testers may pursue various career paths, including Project Manager, Scrum Master, Business Analyst, and Product manager. Developer, DevOps, etc.,  


    In today's digital world, software quality is essential to business success. As more companies invest in software development to solve their problems, software testing is rising. Global market insights estimate that the software testing market will reach USD 40 billion by 2027, growing at a CAGR of more than 7%. 

    Due to new trends, software testing can undergo significant changes in the coming years. Keeping up with new technologies, tools, and trends is essential for testers as they strive to meet the increasing expectations of organizations. It is becoming challenging for testers to keep up with trends such as Agile, DevOps, Machine Learning, IoT, Blockchain, testing automation, testing mobile applications, etc.  

    Software testing is one of the most exciting and in-demand career options. The software testing profession offers excellent growth opportunities. You've come to the right place if you're seeking a career in software testing but are unsure how to get started. Learn software testing with KnowledgeHut.  Learn software testing by applying testing skills in a work-like environment -  KnowledgeHut courses for Software.

    Frequently Asked Questions (FAQs)

    1Is software testing easier than development?

    Testing software isn't easy. The job of a software tester is challenging. Software testing differs from software development and cannot be compared. There is a misconception that anyone can test software. Software testers should possess a broad range of skills to be successful.  

    2Are testers alone responsible for Software Quality?

    Quality is everyone’s responsibility. The responsibility for quality does not lie solely with Testers. Every member of the team is responsible for quality.  

    3What tools should I learn as a new tester?

    Most new testers start chasing automation tools at the beginning of their careers. I recommend gaining a solid understanding of software testing fundamentals first. Ensure you are proficient in at least one programming language before learning tools.  

    4Is automated testing replacing manual testers?

    No. Automated tests can compare expected and actual results. Testing experts differentiate between testing and checking. Testing is more than just checking. Testing is a complex and intellectual activity that requires experimentation, analysis, strong reasoning, and decision-making. There are some things humans can do, notice, and analyze that computers cannot. Our humanity as testers plays a significant role in identifying defects. The purpose of automation tools is to assist testers, not to replace them. 

    5What is STLC in software testing?

    A software testing life cycle is referred to as an STLC. The testing team performs a series of activities to ensure the quality of software or product. The Software 

    Development Life Cycle (SDLC) is part of the software development process. There are various stages in STLC, as shown in the picture below.  

    6What is a Test plan in software testing?

    You can think of a test plan as a project plan for your testing activities. Test plans define the testing strategies, objectives, schedules, estimates, deadlines, and resources needed to complete a particular task. Refer to IEEE 829 Test plan structure.  

    7What is a Test case in software testing?

    A test case is a document with a sequence of steps for verifying a specific functionality. During the early stages of software development, test cases are written referring to requirements and then executed once the software is ready for testing.


    Prashant Hegde


    Prashant Hegde is a passionate testing leader. Prashant specializes in building high-performing teams. Prashant enjoys sharing his experiences by contributing to software testing communities worldwide. He is an accomplished writer and an international speaker. Prashant currently heads the QA team at MoEngage, a leading insights-led customer engagement platform.

    Share This Article
    Ready to Master the Skills that Drive Your Career?

    Avail your free 1:1 mentorship session.

    Your Message (Optional)

    Upcoming Software Testing Batches & Dates

    NameDateFeeKnow more
    Course advisor icon
    Course Advisor
    Whatsapp/Chat icon