How to conduct Java unit testing?

Java unit tests are usually conducted using the JUnit framework. Here is a simple set of steps to perform Java unit testing:

1. Firstly, make sure that the dependency of the JUnit framework has been added to your project. This can be achieved by adding the JUnit dependency in the project’s build file.
2. Create a test class with a name similar to the class being tested, but add a “Test” suffix to the class name. For example, if the class being tested is Calculator, the test class should be named CalculatorTest.
3. In the test class, use the @Test annotation to mark the method that you want to test. For example, if the method you want to test is add(), then the test method should be @Test public void testAdd().
4. In testing methods, you create the object to be tested and call the appropriate methods for testing. Use assertions to verify if the return value of the method meets your expectations. For example, use the assertEquals() assertion to verify if two values are equal.
5. You can run a test class by right-clicking on the test class in the IDE and selecting “Run”.
6. Check the test results. The results will be displayed in the IDE’s console, usually showing the results of each test method and an overall test summary.
7. Based on the test results, if the test fails, fix the errors in the code based on the error message. If the test passes, then other tests can be conducted.
8. Repeat steps 3-7, writing a corresponding test method for each method to be tested.

The steps outlined above cover the basics of conducting Java unit tests. For more advanced testing, additional features of JUnit can be utilized, such as @Before and @After annotations to execute certain operations before or after test methods, and @Ignore annotation to skip specific test methods.