Best Practices for Unit Testing in Java: Tips and Techniques

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Java is so versatile that it is used for building a variety of software applications. But you need to test your code before its implementation. Unit testing is an essential aspect of Java development services that ensures the accuracy and quality of the code. 

It also provides you an opportunity to check your code for bugs and catch them early on. This not only helps in delivering a high-quality product but also saves a lot of time and money. However, you need to implement certain Java Best Practices to ensure that you get the maximum benefits from unit testing your code. 

So, here are some tips for unit testing in Java source code. 

10 Best Practices for Unit Testing in Java

1. Coding after creating test cases

The best Java development company adopts a test-driven approach for building software applications. It is very effective and popular nowadays. In this practice, the tests are composed before you write your Java code. This promotes the kind of thinking that forces you to write a passable code for the tests. 

Implementing this practice can save a lot of time and money since all the bugs and issues are easily identified in the early stages rather than after a product launch. It also provides developers with more clarity on how they should achieve their objectives. As they get to understand what their end product should look like while writing the test cases. 

The aim behind this Java development practice is to encourage developers to think about a problem more thoroughly. This leads to fewer bugs and better design.

2. Isolate Your Unit Tests from External Influence

The unit tests must never rely on any external dependencies like network connections, databases, or any external system. Therefore it is necessary to isolate unit tests from external dependencies.

After isolating the unit tests, developers use mocks and stubs to simulate the external dependencies’ behavior. It simplifies the entire process. And what’s more? Developers can quickly script out the tests without any need to set up or maintain external systems. 

3. Automate Where Possible

Test automation is trending. It frees the developers from the burden of writing and executing the tests. Automating unit tests can increase its usefulness and its efficiency. Moreover, if you use a build tool such as Gradle or Maven, you can simplify the process of executing unit tests. 

Test automation would save a significant amount of time too. When tests are automated, their execution becomes more quick and consistent. Furthermore, the results will also be analyzed and reported automatically. 

4. Keep The Tests Small and Concentrated

Every test is meant to test only a single aspect of code. To keep the tests running smoothly, one has to be quickly able to identify where the test fails. 

Understanding and handling become easy for developers if the tests are more focused on specific sections of the code. Moreover, the execution of these tests will be easy since they are run in a CI environment. 

5. Define Code Coverage

The evaluation of a section of code that is tested is called code coverage. To ensure that your code is tested thoroughly and that you get comprehensive findings, it becomes essential to determine the code coverage. 

There are two things you need to assess to determine what percentage of your code is examined under unit testing: 

• All the classes in your project. 
• All the tests related to those classes. It may be written by yourself or other developers. 

6. Mock External Dependencies

We already talked about isolating unit tests from external dependencies and that we should mock external resources in the tests. We will talk further about those practices in this section. 

External dependencies are mocked to simulate the behavior of components in the apps, this helps reduce the consumption of external resources and also streamline the unit testing. 

Moreover, there are many benefits of mocking. For example, you can test how your app manages errors from HTTP requests through REST API calls. Some of the popular mocking frameworks include Mockito and Powermock. 

7. Validating test outputs using assertions 

Developers use assertions to validate the expected output of the unit testing of a code. This helps them ensure that the code is working as expected. And if it isn’t, they can know where the problem lies. 

Statements that check whether a condition is true or not, are called assertions. They are essential to validate that the code’s output is correct. It is measured by checking whether the test results are as same as the expected results or not. 

Assertions also help in catching the bugs and other errors that normally go unnoticed. Quickly identifying the issues with the code also makes it easier for developers to debug it. 

8. Use Proper Names to Test Methods

Assigning meaningful names to the test method along with a proper description is necessary. It enables the other developers to know what is tested, why it is tested, and what objectives it seeks. 

Updating and maintaining unit tests becomes easier over time if it has a consistent and clear naming convention. It also leads to increased collaboration between developers.

9. Keep Unit Tests Up-to-Date

As you keep your code up to date, you need to keep updating your code too. The tests need to be revised to fit the new tests of those changes made in the code. This helps ensure that the unit tests are correctly testing the code behavior and that it will identify the issues and bugs early. 

10. Create Independent Test Cases

Unit tests are conducted to test different aspects of a source code. Therefore, every unit test needs to be created and run independently. From a comprehensive suite of Java unit tests, developers could run any test, at any time in whatever order they see fit. They can also have it pass or fail quickly. This allows the developers to have a suite of independent tests they can run promptly without further unit testing. 

Final Thoughts on Java Unit Testing

As much as it is necessary to follow the best programming practices, it is equally important to follow the best testing practices. Certain points like keeping tests independent and updated might not seem effective at first sight but their practice is interconnected to the programming practices which eventually helps you keep your code clean and of high quality. Therefore, it is safe to say that implementing Java best practices enables the developers to make the most of their unit tests, and your development life cycle.