Software Testing Basics: Testing Types Explained

by Thijs Kok, on March 9, 2021

Summary: This article explores the distinctions between various types of functional and non-functional testing.

Table of Contents

  1. A Quick Introduction to Software Testing
  2. Types of Functional Software Testing
    1. Unit Testing
    2. Integration Testing
    3.  Functional System Testing
    4. User Acceptance Testing
  3. Types of Non-Functional Software Testing
    1. Performance Testing
    2. Security Testing
    3. Usability Testing
    4. Compatibility Testing 


No matter what type of software or solution you are developing for your clients, its success will be measured by its quality, reliability, and ability to meet the customer’s needs. 

In order to deliver high-quality solutions, it is vital to incorporate structured software testing into your development processes so defects can be identified before a product is launched into the market or delivered to a customer. 

Although there are many different types of software testing that can be conducted at different phases of development and with different groups of stakeholders, tests generally fall into two types: functional and non-functional.

In this software testing basics article, we explore these two groups of tests and how they can help verify that your software will meet your customers’ expectations.

A Quick Introduction to Software Testing

No matter what type of software development methodology you utilize—waterfall, incremental, or agile—best practices call for dedicated time and resources to be applied for comprehensive and structured testing of your product during and after initial development.

Although the specific tests can be sequenced slightly differently in each development methodology and each has different purposes, generally tests are performed to determine:

  1. If the software is capable of performing as expected, also known as functional testing
  2. How well the system works, known as non-functional software testing

These tests can be completed using either a “white box” technique, where the internal code, design, and structure is known by the tester(s), or a “black box” test, where the user is unaware of the internal mechanics and relies only on the interface.

In all cases, the requirements used to develop or update the software are used to develop the test cases for measuring performance in the testing phases.

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Types of Functional Software Testing

Functional software testing is focused on the product’s ability to meet the specified business requirements, ensuring that it performs as expected when put into operation by a customer.

There are a number of functional tests that can be performed to evaluate how well it meets these requirements. These include: 

Unit Testing

Testing that breaks software into individual, isolated units of code or models to determine if that segment works appropriately. This testing, usually done by developers, can occur as units complete initial development or once a series of them are ready.

Integration Testing

After each unit is tested, multiple related components of code or application functionality are tested for their ability to work together properly, such as the completion of a multi-stage process or workflow. For example, a user entering data, the system compiling and analyzing it, and then the ability to generate a report.

Functional System Testing

Following integration testing, the larger system is tested from end-to-end for the solution’s ability to meet the specified business requirements. This includes all workflows, outputs, inputs, and configurations.

User Acceptance Testing

Up to this point, testing is usually completed by an internal development team. This form of testing puts the entire solution in front of an actual or sample customer who independently runs test cases against the business and technical requirements. Once the customers “accept,” or confirm, that the requirements are satisfied, the product is considered ready for deployment or delivery. 

Types of Non-Functional Software Testing

While functional software testing is focused on ensuring a product will meet the identified business objectives and requirements, non-functional software testing is concerned with a system’s performance, reliability, security, and the usability of its interface. In other words, the following types of tests ensure that the software works well.

Performance Testing 

Also known as load testing, this measures the software’s ability to meet the necessary responsiveness, speed, stability, and reliability requirements as it performs workflows under a range of loads.

Security Testing 

Security testing conducts a search for and the attempted exploitation of potential vulnerabilities that could impact the integrity and availability of a solution or its data and resources.

Usability Testing 

As the name implies, this is an evaluation of how easy or intuitive the software is to use. This type of testing is often performed by real potential end users.

Compatibility Testing 

Similar to integration and system testing, these tests evaluate the ability of the software to run across a range of operating systems, hardware platforms, application environments, and networks. 

Bringing It All Together

Testing is an opportunity to refine your software and ensure that it meets your customers’ needs. Although it can be a stressful and tedious process, taking the time to perform the various types of testing can enhance your ability to deliver a product that elevates your brand and builds customer loyalty.

To make your testing experience more efficient, effective, visible, and collaborative no matter your device of choice, you can utilize a comprehensive test case design and test management platform like TestMonitor. Our platform is specifically designed to manage the full lifecycle of testing and integrate into your existing technology ecosystem.

To learn more and to get your own free trial, contact one of our TestMonitor experts here.

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