- 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.