Whitepaper: JUnit Basics - Getting Started with JUnit and Using Automation to Create Unit Tests

Despite the power of JUnit, development teams often struggle to achieve their quality and security goals for their projects. Unit test automation tools like Parasoft Jtest remove these roadblocks and automate the mundane aspects of unit testing.

Find out how Parasoft Jtest leverages the development team’s existing investment in test and mocking frameworks, gives developers their time back and significantly enhances product quality.


Download the whitepaper for a complete tutorial on how to set up, write and run JUnit tests and scale unit testing like a pro with automated Java testing.

Focus areas:
  • What is unit testing?
  • What is JUnit?
  • How to set up JUnit
  • How to run a JUnit
  • Reducing unit test burden with automatic JUnit test creation
  • Understanding the value of JUnit testing requires a full understanding of unit and regression testing. You must also understand why they’re a critical best practice.
  • Unit testing is a form of white box testing in which test cases are based on knowing the internal structure. The tester chooses inputs to explore particular paths and determines the appropriate output. The purpose of unit testing is to examine the individual components or pieces of methods/classes to verify functionality, ensuring the behavior is as expected.
  • The exact scope of a “unit” is often left to interpretation, but a nice rule of thumb is that a unit should contain the least amount of code that performs a standalone task (e.g. a single method or class). There is good reason to limit scope when unit testing – if a test is constructed that incorporates multiple aspects of a project, focus shifts from functionality of a single method to interaction between different portions of the code. If this larger-scope test fails, the cause of failure is much harder to determine.
  • Regression testing makes certain that the latest fix, enhancement or patch didn’t break existing functionality. Regression testing accomplishes this by testing the changes made to the codebase. Changes to code are inevitable, whether they’re modifications of existing code or adding packages for new functionality. Within this change lies the most risk, making regression testing a required practice.

Benefits of unit testing

  • Isolation and focused testing
  • Assuring behavior of individual methods or pieces of methods
  • Ensuring that modification of code doesn’t cause regressions
  • Boundary analysis, checking for invalid/bad input, testing limits
  • Test every aspect of the method for better coverage

While unit testing is incredibly powerful, not all developers are doing it effectively because unit testing requires knowledge of the code and application and is also time-consuming and tedious.

It’s helpful to deploy powerful unit testing tools like Parasoft Jtest that can remedy much of the pain associated with creating and maintaining JUnit and save developers’ valuable time.

JUnit is an open-source framework used to write and run repeatable automated tests in Java and plays a major role in automated regression testing.

The JUnit framework has evolved over time. The most notable major change is the introduction of annotations which accompanied the release of JUnit 4, providing an increase in organization and readability of JUnit. Note: examples in this white paper are written for both JUnit 4 and 5 and are marked thusly.

Key notes on how to set up and run JUnit properly

  • Popular IDEs like Eclipse and IntelliJ already have JUnit functionality installed by default.
  • If you’re not using an IDE or relying solely on a build system such as Maven or Gradle, the installation of JUnit 4/5 is handled via the pom.xml or build.gradle, respectively.
  • It’s important to note that JUnit 5 is split into 3 modules, one of those being JUnit Vintage that supports annotation/syntax of JUnit 4 and 3 (although usage of JUnit 3 is only typically seen in much older projects).
  • JUnit 5 is backwards compatible with JUnit 4, allowing for a gradual transition to the newer framework.
  • There are three ways to run JUnit:
  1. Straight from the command line
  2. From the IDE (Eclipse and IntelliJ)
  3. Using build systems (Maven and Gradle)

*For a complete step-by-step breakdown on how to properly set up and run JUnit4 and JUnit 5, download the white paper.

  • Creating unit tests is very tedious and distracts from the more interesting, impactful parts of a project.
  • The code itself is repetitive and often requires as much effort as the code under test. On top of that, the unit test code requires fixing and debugging just as any code does.
  • Fortunately, unit tests lend themselves very well to automation, so you can use Parasoft Jtest to simplify test creation, reduce the amount of debugging and fixing and collect results and metrics to feed project analytics.

About Parasoft

Parasoft helps organizations continuously deliver quality software with its market-proven, integrated suite of automated software testing tools. Supporting the embedded, enterprise, and IoT markets, Parasoft’s technologies reduce the time, effort, and cost of delivering secure, reliable, and compliant software by integrating everything from deep code analysis and unit testing to web UI and API testing, plus service virtualization and complete code coverage, into the delivery pipeline. Bringing all this together, Parasoft’s award winning reporting and analytics dashboard delivers a centralized view of quality enabling organizations to deliver with confidence and succeed in today’s most strategic ecosystems and development initiatives — security, safety-critical, Agile, DevOps, and continuous testing.