While many industries were affected by the pandemic and suffered losses, the software applications and information technology industry was at its peak and kept growing. Today, the trends like artificial intelligence, machine learning, the internet of things, cloud computing, and many others swamped the software development market and created a huge impact globally. In the production of software applications, also known as the software development life cycle (SDLC), software testing is one of the most important steps. Software testing is a diverse task to find defects or errors in software. It is a process of examining a software’s performance, behavior, and value under test by validation and verification.
There are various types of software testing, and each type has its own features, advantages, and disadvantages. And based on the requirement, a tester selects the type of software testing to be used. The types of software testing are a long list and have more than 20 types of testing. To make it simpler, the types of software testing can be divided into two parts, manual and automation testing. The manual testing takes the box approach of testing, including white, black, and grey box testing, and further, the black box includes functional and non-functional testing.
The Box Approach of Software Testing
There are various software testing methods, and traditionally the in box approach is divided into three types, white-box, black-box, and grey-box testing. The white-box and black-box testing take the approach of describing a tester’s point of view when designing the test cases. And grey-box testing is a hybrid approach that develops tests from specific design elements.
White-box testing is inspecting every line of code before the tests even start. It verifies the internal structures or working of a program as opposed to the functionality and is also known as clear box testing, glass box testing, transparent box testing, or structural testing. The source code and programming skills are used in white-box testing to design test cases. These test cases involve verifying the product’s underlying structure, architecture, and code to validate input-output flow. Generally, white-box testing is applied at the unit level but can also be applied to integration and system levels of software testing types.
Black-box testing (aka functional testing) is a manual testing technique where testers in software engineering analyze the requirements of the software, look for defects or bugs, and decide to send it back to the development level for rectification. In this approach, the software is treated as a black box, and the examination is done without any knowledge of the source code. The testing includes methods like equivalence partitioning, boundary value analysis, decision table testing, fuzz testing, and use case testing. Black-box testing is categorized into functional and non-functional testing, which is then divided into different types of software testing that are discussed below. Additionally, black-box testing can be applied to all levels of software testing, including unit, integration, system, and acceptance.
Grey-box testing is a type of testing in software engineering that tests the software or application with partial knowledge of the internal structure of the software. The testing uses reverse engineering to determine the errors. The goal of grey-box testing is to find and identify defects resulting from improper code structure and irregular use of the software. Grey-box testing determines intelligent test scenarios from the provided software’s limited information that are applied to data type handling, exception handling, and more.
List of Types of Software Testing
Here the list consists of the main levels of software testing after functional and non-functional software testing. The first four types, unit, integration, system, and acceptance testing, come under functional testing. And the rest types, security, performance, usability, and compatibility, are under non-functional testing.
1. Unit Testing
Unit testing is the first level of functional testing in software testing, performed on an individual unit or component to test for correction. It is called unit testing because the tester examines the software module independently or tests all the module functionality. Testers often use test automation tools like NUnit, Xunit, and JUnit to execute unit testing, and each unit is viewed as a method, function, procedure, or object. The objective is to validate the performance of unit components. Unit testing is a curial part of types of testing in SDLC as most defects can be identified at the unit test level.
2. Integration Testing
Among software testing types, interaction testing is where two or more modules of an application or software are logically grouped and tested altogether. This testing is the second level of functional testing that focuses on the defect of an interface, communication, and data flow between modules. The objective of the testing is to test the statement’s accuracy between each module. Integrating testing is further divided into two parts, incremental and non-incremental, comprising four different types of software testing: top-down, bottom-up, sandwich, and big-bang testing. Top-down and bottom-up incremental integration testing works by adding the modules incrementally at each step and then test the data flow between the modules. And the difference between the two is that the modules added in the top-down must be the child of the earlier module, and in the bottom-down, the module must be the parent of the earlier one. When the data flow gets complex and difficult to classify a module as parent and child, non-incremental integration is applied.
3. System Testing
System testing is the third level of functional testing, also known as end-to-end testing, in which the test cases are operated while the test environment and production environment are parallel. In system testing, each attribute of the software goes under test for the working of end features based on the business requirements, and then the software product is analyzed as a complete system. Various software testing types are performed under system testing, including end-to-end, smoke, sanity, monkey, and so on.
4. Acceptance Testing
Acceptance testing (aka user acceptance testing) is a type of testing in software engineering where the client or business tests the software with real-time business scenarios. This is the fourth and final level of functional testing, after clearing the test, the software goes into production. The testing is a quality assurance process determining the degree of success of meeting the clients’ requirements and getting thier approval. Several methods can be used in acceptance testing, such as Alpha testing, Beta testing, and operational acceptance testing (OAT).
5. Security Testing
Security testing is a non-functional type of software testing intended to reveal defects in the security mechanism of an information system protecting the data and maintaining functionality. The testing includes checking how the software or application is secure from internal and external threats and how much software is secure from malicious programs and viruses. The tests check to provide maximum security if any cyber attack happens, going on with how software behaves under a hacker attack and how secure and strong is the authorization. A few security testing methods are penetration testing, vulnerability scanning, and risk assessment.
6. Performance Testing
Performance testing tests a software’s stability and response time by applying load in the software. Testers focus on four things in performance testing: response time, load, scalability, and stability of the software. The goal of performance testing is to identify, rectify, and eliminate the performance bottlenecks in software. The testing consists of different types of testing, including load testing, stress testing, scalability testing, stability testing, volume testing, endurance testing, and spike testing, and each test serves one or more focus points. Performance testing is done with tools like Loader.IO, JMeter, LoadRunner, etc.
7. Usability Testing
Usability testing is another non-functional type of testing in software engineering which works from the users’ point of view to check the user-friendliness of the software application. A user-friendly software has two aspects: the application must be easily understood and look appealing and feel good for working on it. The purpose of usability testing is for the application to look appealing and showcase information at a glance. Some of the testing methods in usability testing are exploratory testing, cross-browser testing, and accessibility testing. Additionally, four questions help guide the usability testing process: screening questions, pre-test questions, in-test questions, and post-test questions.
8. Compatibility Testing
Compatibility testing is a non-functional type of testing that validates how software application behaves and runs in various environments, web servers, hardware, and network environments. The goal of the testing is to ensure that software is capable of working on different configurations, databases, browsers, and their versions. There are two types of compatibility testing, backward or downward and forward compatibility testing.