Types of Testing – What are Different Software Testing Types?

Do you know that software testing is more than just finding out development issues? It involves critical thinking to figure out different scenarios where an application can run through problems during real-life usage. And you can do this by knowing and performing different types of testing, which is the foundation of this blog.

We talk about these software testing types and their purpose in SDLC, so you can understand why and when you need them.

What is Software Testing?

According to IEEE Std 829-1998, Software Testing is “the process of analyzing a software item to detect the differences between existing and required conditions (i.e. defects) and evaluating the features of the software items.”With the advent of new technologies and new software releases every day, software testing is gaining more strength and accolades. Today, testing is imperative, and there is no way we can skip it. Testing and development are going hand in hand for a faster release in this Agile world.

Everyone wants stable, high-quality, and functionally correct software that meets all the user requirements. And all this is easy to accomplish with proper Software Testing, which uncovers errors that may be problematic later for the software and subsequently to the clients or the organization.

So, let’s first discuss testing techniques before we move to software testing types.

Software Testing Type Based on Experience or Planning

As the name suggests, experience-based testing primarily runs on the tester’s expertise. Their years of experience are perfect for executing Adhoc and exploratory testing, both of which do not require a detailed understanding of system requirements.

Adhoc Testing

Adhoc testing is an informal and unplanned testing approach where the tester improvises the test cases based on their intuition, experience, and domain knowledge. They do so without predefined test cases or a formal test plan. It allows rapid detection of defects, especially in areas that formal test cases may not cover.

Exploratory Testing

Exploratory testing is a dynamic and concurrent testing approach where testers design and execute test cases simultaneously. It depends on adapting their approach based on real-time feedback and evolving understanding of the application. This type of testing enables testers to detect issues in real-time and gain further experience in validating systems without the need for a comprehensive test plan.

Types of Testing Based on the Testing Objective

Another classification of testing is based on the objective type. Here are some common testing types based on their objectives:

Functional Testing

It is a type of software testing that focuses on verifying that the software functions as expected according to the specified requirements. The goal here is to ensure that each function or component of the software application behaves as intended and that the system meets its functional requirements.

Non-Functional Testing

Non-functional testing is a type of software testing that evaluates the non-functional aspects of a system, such as its performance, reliability, scalability, and usability. Unlike functional testing, non-functional testing is concerned with how well the system performs under various conditions rather than what it does.

Acceptance Testing

This is the final phase of the software testing process and is conducted to determine whether the software system meets the specified acceptance criteria. Acceptance testing involves validating the system against business requirements and ensuring that it is ready for release.

Types of Testing Based on the Test Execution Method

Another software testing type is based on the chosen method of execution. Two options fall into this category:

Manual Testing

Manual Testing is a traditional software testing approach where test cases are executed manually by a human tester without the use of any automation tools. Testers carefully execute test cases, compare the expected outcomes with the actual results, and report defects or issues. It is labor-intensive and requires testers to go through the software application step by step.

Automated Testing

Automated Testing is a software testing technique where specialized tools and scripts are used to perform tests on the software application with just enough human intervention. Instead of manually executing each test case, automated testing relies on pre-scripted test scenarios that testers can run automatically. This software testing technique is efficient for repetitive tasks, regression testing, and scenarios where many test cases need to be executed across different environments.

Types of Testing Based on Test Design Techniques

The design-based testing technique comes from the way test cases are designed and created. There are three types of test design techniques:

Black Box Testing

Black Box Testing is a software testing method where the internal workings or code structure of the application being tested are not known to the tester. The focus is on the system’s inputs and outputs, and the tester treats the software as a black box. Test cases are designed based on the system’s specifications and requirements, and the tester evaluates the functionality and behavior of the software without knowledge of its internal implementation.

Read here- What is Behavior Testing

White Box Testing

White Box Testing, also known as Clear Box Testing or Structural Testing, is a testing method where the tester has knowledge of the internal workings, code structure, and implementation details of the software being tested. Test cases are designed based on the internal logic of the code.

Gray Box Testing

Gray Box Testing is a testing method that combines elements of both Black Box Testing and White Box Testing. In Gray Box Testing, the tester has partial knowledge of the system’s internal workings. The tester uses a combination of external inputs and knowledge of the internal code to design test cases and assess the system’s behavior.

Testing Techniques

We will discuss several testing types based on their application and approach.

Testing Techniques Based on the State of the Application

On a broader level, testing techniques can be divided into two types based on the state of the application. To test the application under test against functional or non-functional requirements, two testing techniques are used(static or dynamic).

1. Static Testing (Verification): Verification implies, “Are we building the product right?”

Static testing approaches are used to detect faults in an application under test without executing the code. Static testing is performed to avoid defects early in the development cycle, lowering the cost of correcting them.

In Static Testing, code is not executed. Documents like requirements documents, design documents, code are reviewed and review comments are provided at early stages of Software Lifecycle. It is a preventive measure, which eliminates defects at early stages and hence, the ROI is high. Examples of Static Testing – Walkthrough, Reviews, Static Code Review, Inspection.

Read here more on Build Verification Testing

2. Dynamic Testing (Validation): Validation implies,“Are we building the right product?”

Dynamic testing approaches are used to test the dynamic behavior of the application under test by executing the code base. The fundamental goal of dynamic testing is to test the application using active inputs, some of which may be permitted by the requirements (Positive testing). In contrast, others are disallowed (Negative Testing).

 In Dynamic Testing, the code is executed. The program is run and inputs are provided, the actual results are validated against expected results. Defects are found and fixed, it is performed at later stages of the Software Lifecycle. Hence, the ROI is low. If the defect is fixed, it involves more time and is more expensive. Examples of Dynamic Testing – Unit testing, System testing, Integration testing, Performance testing, Security testing. 

Testing Techniques Based on the Methodology or Approach

To begin, you should be aware that numerous testing approaches have been developed, abandoned, and obsessively followed in the software testing area. They outline the project management testing methodology.

1. Agile Methodology
2. Waterfall Methodology
3. Spiral Methodology
4. XP (Extreme Programming) Methodology
5. Incremental Methodology
6. Verification and Validation Methodology

Based on the methodology or approach, testing techniques can be classified as below:

Black Box Testing

The Software Program is considered as a black box, and the user is not interested in the internal structure of the box. The output from the black box is validated against the input provided irrespective of the internal code structure.

Examples

• Boundary Value Analysis
• Equivalence Partitioning
• Decision Table
• Exploratory Testing
• Error guessing

White Box Testing

The internal structure and design of the code are known to the user; hence all the logical paths are tested under White Box testing. It is also known as Glass Box or Clear Box testing since the user knows the internal logic and structure of the code inside the box.
 Examples

• Statement Coverage
• Path Coverage 
• Decision Coverage

Grey Box Testing

Contains features of Black Box as well as White Box testing, where the tester has limited knowledge of the internal structure of the application e.g. data structures and algorithms. Unlike, White Box testing, testers do not need to have complete programming knowledge. Grey Box Testing proves to be effective while performing Penetration Testing and Integration Testing. Since both, Penetration and Integration require partial knowledge of the internal structure.

Check out – Feynman Learning Technique in Software Testing

Different Types of Tests

On a broader level, software testing types can be divided into two types, Functional testing and Non-Functional testing.

What is Functional Testing?

Functional testing is a sort of testing that aims to determine whether each application feature functions following the project’s requirements. Functional testing deals with functional specifications or business requirements. This testing is critical for evaluating the software’s quality and functionality. Each function is compared to the corresponding condition to see if its output matches the end user’s expectations.

What is Non-Functional Testing?

Non-Functional testing deals with the performance of the application. Non-Functional testing is equally important as Functional testing is since no one will want to use an application that is not scalable or secure, or let’s say, the application can’t handle a load of many DB operations at an instance. Hence, the application’s performance in various areas is tested during Non-Functional testing.

Let’s dig deeper and find out more about different software testing types.

Functional Testing

1. Basic Functionality and conformance of the application with Functional Requirements are validated.
2. It is a type of Black Box testing; hence the internal structure and design of code are not checked.
3. Test cases are created, then run on the system and the actual results are validated against the expected results.
4. Any deviation from expected results is logged as defects and then fixed by the development team. 

What are Functional Testing Types?

• Unit Testing– The most basic unit or component of an application is tested usually by the developer to ensure the smallest testable code is working fine. It is a White Box testing technique and appears at the bottom of the V-Model, i.e. it is the first software testing type to be carried out in SDLC. Know here the difference between Unit Testing and Integration Testing. Know here the difference between Unit Testing and End to End Testing

• Integration Testing- When two or more components or units of the software are integrated together, they need to interact with each other in the form of commands, data exchange or DB calls. Integration testing is performed on them as a single cluster to check that the interaction between them is happening, as expected. Know here in detail about Android Integration Testing.

• Interface Testing- It comes under Integration testing, the correctness of data exchange or transfer between two components is tested in Interface testing. For e.g. One component creates a .csv file as output, the other connected component processes the .csv file into XML and sends to the third component. During this data transfer, the data should remain intact and all the components should be able to process the file and send the file to the next component successfully.
• System Testing- All the modules of the application are combined and the whole system is tested as a single unit for correctness against the requirement specification. Learn More: Difference Between Acceptance test Vs System Test.
• Regression Testing- Whenever there are some code fixes, or any functionality enhancement, the code is modified. Regression testing makes sure that these code changes have not injected any new defects in the code and that the previously working functionality is also intact and working. Find here about the difference between Regression Testing and Retesting
• Smoke Testing– Performed on initial unstable builds, whenever a new build is released by developers, testing team performs Smoke testing to be sure that all end-to-end functionalities are working. If any of the major functionality is broken due to a new build, the build is rejected and sent again to developers. This is performed to ensure that new code changes have not broken any major functionality and the build can be taken forward for the next level of testing.
• Sanity Testing- It is normally a subset of Regression tests; it is performed whenever there is a new build released for a stable application. Only after running the Sanity test suite, the build is taken forward for the next level of testing. Difference between Smoke and Sanity is- Smoke testing is performed on an initial unstable application, whereas Sanity is performed on a stable application.
• User Acceptance Testing- It is the last level of testing in a V-Model, parallel to the requirement analysis phase. It defines how well the application is accepted by the real end-users. The fulfilment of business requirements, by actual users, is checked, in a real environment.

Non-Functional Testing

1. In Non-Functional testing, important non-functional aspects of the application are tested like Security, Scalability, Performance etc.
2. How well the application will perform under stressful conditions of Database, Users, Data Load etc.
3. From a user’s perspective, is the application usable, maintainable, scalable and secure to gain user’s confidence and trust.

What are Non-Functional testing types?

• Performance Testing– The performance of the application is measured while subjecting the application to real-world conditions. During this testing, performance parameters like response time, scalability, stability and efficiency of resource usage etc. are monitored; hence it is useful in finding out when the application will degrade. It will help in enhancing the application design or architecture in a way that reliability and fast response time is ensured.

• Stress Testing– Application is subjected to anomalous conditions, which will not happen under normal circumstances. Load on the application is increased to the point that it breaks and the application behaviour is recorded. Few questions that are answered via this testing are –  How the system behaves under stressful conditions? if it crashed will it be able to recover itself and restart?

• Volume Testing– Aim of this testing is to ascertain how well the system behaves when a large volume of data or data operations are handled by Database. Will the database be able to store and process a huge volume of data? Will there be an issue due to the huge data volume?

• Load Testing– The performance of the application under expected load as in the real world is measured. All possible loads on the application are simulated and the performance is checked. For example, on a normal day, 1000 users are expected to visit a website, the performance of the website is measured by simulating concurrent 1000 users, this is a normal load during real-world usage. However, when a promotion is running, the number of users may increase to 2000, in this case, the application is tested for a load of 2000 users also because this is expected load. Unlike Stress Testing, abnormal conditions are not tested, only the expected load i.e. the load that application is expected to face in the real world is tested on the system. If the application degrades under load, then changes in the architecture could be made to avoid such bottleneck.

• Security Testing- Security of the application from the point of view of the network, data, system and the application is tested. Any non-authorized person should not be able to access the application and should not be able to access any confidential data. This testing ensures customer reliability and confidence in the application. Penetration testing is an example of Security testing.

• Scalability Testing- In case the application needs to be scalable in future, will the architecture and design allow? For example, if we add more servers, have more database transactions, increase the user load in the future, will our application allow that? This is tested under Scalability testing of the application.

• Usability Testing– Deals with the usability of the system from a user’s perspective. Is the user able to navigate through the application without any help? Next time, when the user visits the application, is he able to remember the application without any help or problem? How efficiently a user is able to use the system? All these questions are answered via usability testing.

• Maintainability Testing– Designing an application is one thing, and maintaining the application for future expansion and requirements is another and equally important. How well the application accommodates the changes and updates done on the code or system, comes under maintainability testing.

• Compatibility Testing – The compatibility of the application is tested with regard to different Operating Systems, Browsers, Hardware, Network capacity, Devices etc. The application should be able to perform well on the prioritized environments by the customer.

Check Out Other Kinds of Testing: SAP Testing & IOS App Testing

Manual and Automation Testing

If we categorise the testing services based on the effort(human or machine) we have two broad categories.

Manual Testing

As the name suggests, manual testing is carried out manually by real people. Testers perform manual testing by following the test steps in the test case; clicking, providing inputs on the application and finally validating the test results. Because humans are directly involved in this process, there could be chances of error and it will be time consuming. However, manual testing becomes imperative for scenarios where automation testing is not possible.

E.g. Usability Testing – where the tester is testing the application from the user’s perspective, or its user-friendliness.

Automation Testing

Automation testing involves the use of automation tools and scripts to run the test cases automatically, without manual intervention. These tools run the test cases, record the test results and sometimes log the defects in the defect tracking tool. Time-consuming and repetitive test cases like regression testing cases are an ideal fit for automation testing.

E.g. Selenium, Testsigma, TestComplete etc.

Check the details on the benefits of automated testing here: Why Automated Testing | Advantages of Automated Testing.

If your organization is deciding on whether to implement automated testing, check here: When to Choose Test Automation Framework Over Manual Testing

If you have decided to pursue automation and are looking for a tool to get started with test automation then this article is for you: 10 Points to Help You Choose the Right Test Automation Tool

Conclusion

To conclude, below quote from Bill Gates defines an organization perfectly:

“We have as many testers as we have developers. And testers spend all their time testing, and developers spend half their time testing. We’re more of a testing, a quality software organization than we’re a software organization.”- Bill Gates

And this surely emphasizes how important software testing is.

Knowledge of the various software testing types and when to use which software testing type is crucial for a good tester. Each software testing types has its own importance and usefulness in the testing Life Cycle of an application. A well-equipped tester with required knowledge surely wins half the battle.
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Frequently Asked Questions

What is Testing in SDLC?

SDLC is a methodical approach for developing software that ensures its quality and correctness. The software development lifecycle (SDLC) testing phase is where you focus on research and discovery. The SDLC process is designed to provide high-quality software that satisfies customer requirements. During the testing phase, developers determine whether their code and programming meet the needs of the customer.

What are Testing techniques?

Software testing techniques are methods used to test the application under test with functional or non-functional business requirements. Each testing technique aids in the detection of a certain sort of fault. Techniques that detect structural problems, for example, may be unable to detect defects in the end-to-end business flow. As a result, several testing approaches are used in a testing project to ensure that it is completed with acceptable quality.

What are the 7 Phases of SDLC?

The seven phases of SDLC include planning, analysis, design, development, testing, implementation, and maintenance.

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