There are many things any Java developer must be proficient in, including various popular programming languages, libraries, and even frameworks. However, there's one more thing that has become increasingly important for an experienced Java developer -- automation testing. The rapid rise of DevOps has put the spotlight on automation testing, with more and more companies seeking out developers adept at not only writing unit tests, but also with a decent understanding of different unit testing frameworks, tools, and libraries.

One might say that JUnit is an accomplished resource that has successfully assisted developers with automated unit testing for a while now. However, testing, as a concept, has evolved significantly over the past few years. It has resulted in the emergence of a variety of Java-based open-source frameworks that are quite different from JUnit in several regards, including business logic and validation terms.

So, here's a list of the different frameworks, tools, and libraries that Java developers can leverage for their unit as well as integration tests.

1. JUnit: We'll start with this one because it is perhaps the most used tool for writing unit tests for Java code. Nearly all significant IDEs, including NetBeans, IntelliJIDEA, and Eclipse, offer integrations for JUnit. It means that a developer cannot only write but also execute unit tests directly from these IDEs. Moreover, it would also help to remember that JUnit supports Java 8 features and that it can be used for the unit as well as integration testing.

2. JBehave: JBehave, typically used in combination with Selenium WebDriver for Java, enables Behaviour Driven Development (BDD) testing. So, in case you are wondering what that is, well, it is design philosophy wherein the testing is primarily based on the app's behavior. The goal of this framework is to make help even beginners become acquainted with the concept of BDD.

3. REST Assured: We'll admit that the testing, as well as validation of REST services in Java, is usually much more challenging in dynamic languages like Groovy. To that end, REST Assured offers ease of using such languages within the domain of Java. Therefore, REST Assured is an excellent tool for REST API integration tests.

4. Serenity: An open-source library for behavior-driven testing, Serenity not only enables developers to write well-organized and better-supported acceptance criteria but also expands both WebDriver and JUnit's functionality. Interestingly, it was first introduced to the market as 'Thucydides,' but the name was changed owing to the challenging pronunciation of that name.

5. TestNG: Though TestNG is modeled on JUnit and NUnit, this testing framework differentiates itself with functionalities that not only render it to use but also make it much more powerful. These functionalities include running tests in randomly large thread pools with the availability of several policies, annotations, and more.

These are some of the most popular unit testing and integration testing tools, frameworks, and libraries that make elevate a Java developer from being useful to being an expert. Also, it would help if you kept these things in mind when you set out to hire expert Java programmers for your development projects.

Author's Bio: 

Kaushal Shah manages digital marketing communications for the enterprise technology services provided by Rishabh Software. This article is written with an emphasis on the various Java test frameworks and libraries for automation testing.