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There are seemingly countless unit testing tools available, so figuring out which is best for you is tough. You want to ensure that each part of your code performs its intended function correctly but need to figure out which tool is the best fit. I've got you! In this post I make things simple, leveraging my experience using dozens of different testing tools to bring you this shortlist of the best unit testing tools.

What are Unit Testing Tools?

Unit testing tools are software applications used in the development process for testing individual units or components of a software application's code. These tools allow developers to validate each part of the code independently, ensuring that it performs as expected. Unit testing is a critical step in software development, focusing on the smallest parts of an application, like functions or methods.

The benefits and uses of unit testing tools include early detection of bugs, making it easier to identify and fix issues at the development stage. They improve the overall quality of the code and facilitate smoother integration of different components. Unit testing tools also support code refactoring, allowing developers to modify and optimize the code with confidence. This leads to more reliable and maintainable software, ultimately speeding up the development process and reducing long-term costs.

Overviews Of The Best Unit Testing Tools

Here’s a brief description of each unit testing tool to showcase each tool’s best use case, some noteworthy features, and screenshots to give a snapshot of the user interface.

Best programmer-oriented, unit-testing php-based framework

  • Open source and free

As its name suggests, PHPUnit is a unit testing framework for PHP developers. Its blueprint and building block is derived from the xUnit design for the unit testing system. PHPUnit can be run from the command line. 

One of its main features of attraction is how it enables PHP developers to create pre-written assertion methods. PHPUnit’s assertion methods encapsulate testable logic and are used to test for the expected behavior of units, subsequently highlighting results by turning green/red.

PHPUnit is integrated with virtually all of the main PHP development such as Laravel, Symfony, Zend, Yii, CakePHP, and so on. 

PHPUnit is open source and free.

Best Java mocking framework for writing & maintaining tests

  • Free

Mockito is an open-source mocking framework with a simple and clean API that enables you to write readable, verifiable tests. It enables both testers and developers to create Mock objects to facilitate easier testing. 

Mockito suits DevOps and QA teams that place a high value on the maintainability of their test suites. It provides clean discernible verification errors, in addition to allowing you to reuse mocking classes and interfaces for better efficiency. Mockito provides sophisticated yet easy ways to track failed test verifications to the actual point of interaction in the code.  

Legacy code can be difficult to work with but Mockito provides the means for it to be refactored so it can be more testable. Mockito makes this feasible by decoupling testing logic from code implementation. 

Mockito integrates with Cucumber, Spring, and Jenkins, along with built-in support for managing a mocking life cycle with JUnit.

Mockito is a free, open-source library.

Best to simplify a broad range of advanced testing needs

  • Open source and free

TestNG stands for Test Next Generation, an open-source framework for Java-based testing. It lives up to its name by supporting fairly advanced features to write powerful tests like grouping test cases along with sequencing and parametrizing. In addition, it also provides automation abilities like the ability to generate customized test reports and easily-to-read code scripts

TestNG covers a range of different test categories such as unit, functional, end-to-end, and integration testing. Because it was inspired by predecessors like JUnit and NUnit, it shares some of their features like annotations, in addition to the new functionality of its own like multithread safe execution and runtime logging. 

It supports parallel test execution based on priority and the selected test order, which makes automation easier and more reliable. It achieves this by executing test cases using file order of execution of methods and TestNG XML. 

TestNG integrates well with such as Selenium, and Gradle, in addition to supporting a variety of tools and plug-ins with Maven, Eclipse, and IDEA. 

TestNG is open source and free.

Best unit testing framework for embedded C or C++ software development

  • Free for 30 days
  • From $109 (£95) for a single user license

Embunit is a unit testing tool for developers working with C or C++. While it can be used for various types of software development, it is primarily aimed at embedded applications. 

Embunit capitalizes on what is basically the worst-kept secret in software development — the fact that developers hate writing tests of any kind. Embunit reduces this mundane task by allowing developers and QA teams to specify what they want the test case to do as a sequence of operations. It then proceeds to make the work of C or C++ programmers easier by auto-generating unit source code. It even goes the extra mile by facilitating the maintenance of units.

Embunit provides you with an XML file that has the definition of test cases. Because its XML schema uses meaningful and simple words, Embunit makes it easy to understand and review changes by simply comparing XML files. 

Embunit is designed with flexibility, so it can be customized for a variety of tests for various microcontrollers and hardware platforms. However, it isn’t tied to any toolset but is primarily designed to accommodate the common shortcomings of embedded C++ compilers. 

Embunit costs from ~$109 (£95) for a single user license. You can try it for free for 30 days.

Best comprehensive IDE for development, debugging, & test management in .net

  • From $45 per month

Microsoft Visual Studio is a full-fledged software development platform. Visual Studio provides test coverage for developers and testers, allowing them to maintain the health of their codebase through debugging and running unit tests. It provides software professionals with an integrated environment to troubleshoot and find errors before customers do.

Visual Studio also offers an automatic testing feature called Live Unit Testing. It operates in real-time, detecting the tests impacted by the code changes and simultaneously running them in the background. This immediately gives the programmer feedback on whether a particular line of code is failing or passing its test coverage. 

While Microsoft Visual Studio provides debugging and testing capabilities, it also offers Visual Studio Test Professional as a performance testing solution. Test Professional empowers users to create and manage test scenarios throughout the SDLC process. Compared to open source test tools in the market, Test Professional scores high points for its user-friendly and intuitive interface. 

Microsoft Visual Studio and Test Professional integrate seamlessly with other apps in the ecosystem like Microsoft SQL Server and database. 

Visual Studio Test Professional Subscription download is priced at $2,169.00, with renewals costing $899.00. For its Business tier, the Professional and Enterprise subscriptions are priced at $45 per month. 

Best NET unit testing platform for organizing test scripts

  • Free To Use

NUnit is an open-source unit testing tool for the .NET platform and languages. It is also part of the .NET Foundation. NUnit is a convenient framework for writing tests, along with its accompanying documentation. 

It allows developers and QA testers to add relevant metadata attributes to improve a unit test's context. Subsequently, they can run improved tests based on the specific values provided by the metadata. 

NUnit comes with a category feature that makes it possible to mark tests related to a specific feature. In doing so, it allows QA testers to execute a set of unit tests related to that feature, instead of running a multitude of other tests. In addition, it has many built-in assertions that can be read and used fluently out of the box. 

NUnit offers API access that can be used to integrate with third-party apps like Xamarin, Visual Studio, Launchable, TestLeft, LT Browser, Opsera, and many more. 

NUnit is free to use. 

Best simple testing framework for Java & JVM to repeatable tests

  • Free

JUnit is a unit testing framework that allows developers to build up-to-date foundations to test their Java and JVM applications. JUnit is open-source and makes it simple to write repeatable tests. It is currently in version 5 and has incorporated the most recent features of Java.

The framework gives testers the ability to run dynamic tests while writing less code but nevertheless producing clean tests. In addition to assertions and extensions, JUnit also incorporates fairly sophisticated testing features such as method parameters and injecting dependencies.

You can easily integrate and run JUnit from any Java-based IDE such as Eclipse and IntelliJ. JUnit can also be integrated with other software platforms and tools including Java, ScalaTest, LambdaTest, TestContainer, Karate DSL, TestLeft, and so on. 

JUnit is free.

Best GUI-less browser for Java programs

  • Open source and free

HtmlUnit is a command line, Java-based testing framework used for unit testing automation. HtmlUnit provides an implementation of a web browser without a GUI. Hence, it serves as a Java headless browser; which allows developers to perform HTTP requests on websites and parse the HTML content.

GUI-less browsers have the advantage of being used programmatically without the need to be directed by a user. It is a powerful HTML parsing platform that in addition to unit testing, it can also be utilized for web scraping and data mining purposes. 

HtmlUnit is ideal for web application automated testing, as it enables testers to simulate what users can do on a browser such as click events, and submit events. More so, it supports JavaScript and AJAX functionality.  

HtmlUnit also offers users a lightweight implementation of a WebDriver. HtmlUnit Driver is one of the fastest Headless browser drivers available. Headless browsers like HtmlUnit affords testers and QA teams the ability to perform cross-browser testing accurately without requiring the browser on which the application needs to be tested. 

HtmlUnit can be used in conjunction with other development and testing frameworks such as Spring, Maven, and Selenium. 

HtmlUnit is open source and free. 

Best automated testing toolkit for Java developers

  • Open source and free

JMockit offers Java developers out-of-container integration testing, especially for Java EE and Spring-based apps. It is an advanced library that provides automated processes across a range of functions such as mocking, faking, and integration testing.

Among the features it provides are code coverage tools, mocking API for armed with recording and verification syntax, and faking API for replacing implementations. 

JMockit provides more comprehensive mocking mechanisms compared to other equivalent frameworks, for instance, the ability to mock final classes, including private, and static methods. It provides other encapsulation capabilities to enable mock implementations and other instances to execute tests without any explicit knowledge of the actual implementation classes. This subsequently gives JMockit the capability to more accurately verify objects through the use of regular assertions. 

JMockit functionality makes it possible for programmers to spend less time debugging code but more time building features. It provides various APIs for mocking, known as “Expectations API” for mocking dependencies. Others exist for automatic initialization or instantiation of objects, and some for other relevant purposes. 

JMockit is open source and free.

Best to streamline compliance by facilitating defect-free code with Java

  • From $20/user/month (billed annually)

Parasoft JTest provides a comprehensive set of Java testing tools to maintain quality code and comply with industry-based standards. It allows developers, testers, and QA teams to monitor their progress toward their quality goals. JTest makes this possible, in part, by providing the means for creating a baseline for measuring and establishing coding standards.  

Jtest does this by automatically generating compliance verification documentation. It also adheres to modern DevOps practices like agile development cycles. Furthermore, Parasoft enables you to achieve higher code coverage faster by integrating seamlessly into your development ecosystem and CI/CD pipeline. 

Jtest allows you to improve team test efficiency with its runtime unit analysis and AI-infused software testing. Jtest integrates with Jira software, Jenkins, Bamboo, GitHub, and so on.

Parasoft JTest pricing is available upon request.

The Best Unit Testing Tools Summary

Tools Price
PHPUnit Open source and free
Mockito Free
TestNG Open source and free
Embunit From $109 (£95) for a single user license
Microsoft Visual Studio From $45 per month
NUnit Free To Use
JUnit Free
HtmlUnit Open source and free
JMockit Open source and free
Parasoft JTest From $20/user/month (billed annually)
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Other Unit Testing Options

Here are a few more unit testing options that didn’t make the top list.

How I Selected the Best Unit Testing Tools

If you're wondering how I selected the best tools for unit testing, here's where I'll break it all down for you. First of all, I started with unit test tools that have high user review and satisfaction ratings. Then, using my experience in software testing, I discerned what key criteria were most important for unit testing software tools and compared how each of them stacked up against the rest.

I empathize with how much time it takes to source the right software for a job. I do this work so that you don't have to. I've been using and reviewing tools for unit testing for years so you can trust me to do the heavy lifting and compile all the facts you need to make your final decision.

Selection Criteria

After careful consideration, I've determined that these are the most important criteria when selecting the best unit test tools. Here's a brief list outlining the whats and whys of my selection.

User Interface (UI)

Developing software requires writing lots of code. So, the UI should have a clean interface that is minimalist and uncluttered because the unit testing process invariably involves developers juxtaposing substantial source code in an IDE.

Usability

Since developers often need to run tests while simultaneously writing code, convenience and unobtrusiveness is important. Therefore, I looked for tools that are easy to use, especially those tools that can operate seamlessly and be installed as plug-ins.  

Integrations

By necessity unit testing tools have to play nice and interact with integrated development environments (IDE) and other software platforms. So, I looked for tools equipped with APIs to support integration with a wide variety of platforms and compatible DevOps tools.

Pricing

I always look out for the bang for the buck in terms of the value for money exceeding the price paid for a tool. However, most unit testing tools tend to be open source and free, so I predominantly made my evaluation based on the richness of features provided.

People Also Ask

Sometimes while writing I have an “ah-ha!” moment around questions readers might have about the topic at hand. In this case, I’ve compiled some brief Q&As around unit testing tools, what they do, and how they help.

What are the Benefits of Unit Testing Tools?

There are several benefits to using unit testing tools:

  1. Improved code quality: Unit testing tools can help identify bugs and defects early in the development cycle, enabling developers to fix them before they become more significant issues that are harder to resolve. By testing individual components, developers can ensure that each part of the codebase functions correctly and works together seamlessly.
  2. Faster development: Unit testing tools automate the process of writing and executing test cases, enabling developers to test their code more quickly and efficiently. This can help speed up the development cycle, allowing teams to release software faster and with more confidence.
  3. Cost savings: Catching bugs and defects early in the development cycle can save time and money by reducing the amount of time and effort required to fix issues later on. This can also help prevent costly downtime or errors that could impact business operations.
  4. Increased team collaboration: Unit testing tools can help promote collaboration among team members by providing a common framework for testing and debugging code. This can help ensure that everyone is working towards the same goals and that the software meets the required standards and specifications.

What are Unit Testing Tool Key Features?

  1. Automated testing: Unit testing tools are now incorporating automated testing to provide or establish productive testing workflows. These are usually to run test cases to eliminate repetition, reduce time, and remove error-prone manual processes.
  2. Multiple use case testing: The best unit testing frameworks now feature the capability to execute multiple use cases simultaneously. This provides a well-needed productivity boost, especially with huge codebases with several functionalities to unit test, while allowing developers to code and test more effectively.
  3. Validation testing: These features ensure code is sufficiently tested to meet users’ needs and requirements. They encompass mechanisms to effectively test for failures as well as success conditions in code so testers can easily isolate the cause of bugs.
  4. Performance testing: Process of evaluating the speed, responsiveness, stability, scalability, and resource utilization of a system or application under expected and peak load conditions.
  5. Mocking capabilities: Providing developers the ability to create mock objects to replace or control external dependencies in code with an object of predefined behavior. This enables developers to test their own code and override objects and dependencies that don’t need to factor into the narrow snippet of unit code.
  6. Solutions integration: Unit testing platforms need to have native integration with CI/CD tools to assist developers and testers work effectively.
  7. Real-time reporting: Unit testing tools provide instruments for executable documentation so that it can be easy or clear to discern the expected outcomes of a software feature’s functionality.

What Other Testing Resources Do I Need?

If you’re thinking about unit testing tools, then these resources on our site can help you with additional tools and strategies for your testing process:

The Importance of Unit Testing Tools

Test coverage is a cardinal part of the software development lifecycle. Unit testing and test-driven development are tools that should be in every DevOps arsenal of skill sets. The best unit testing tools help to reduce and fix bugs early in the software development lifecycle.

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Eze Onukwube
By Eze Onukwube

Eze has a master's degree in communications with over 10 years of experience as a software engineer. His playground is at the intersection of technology, process improvement, and simplifying IT concepts.