Junit interface framework in the Java library

JUNIT is a widely used Java unit test framework to test the method and functional correctness in the Java class library.It provides rich test tools and assertions, enabling developers to easily write and perform unit testing. When writing and executing unit test using Junit, developers usually follow the following steps: 1. Import the Junit library: First, the Junit library is imported in the Java project to use Junit's test tools and assertions.You can build a junit library dependency item by building tools such as Maven or Gradle. 2. Create a test class: Create a test class, named the original class after the name of the original class.For example, for a class called Calculator, a test class called CalculatorTest can be created. 3. Add test method: Add the test method in the test class.Each test method should be marked with @Test annotations so that Junit can recognize them.The test method should have a VOID return type and should not accept any parameters. 4. Write test logic: In the test method, write test logic to verify the correctness of the original class method and function.You can use the assertion method provided by Junit to check whether the expected output and the actual output are consistent. The following is a simple example that demonstrates how to use Junit to test a simple calculator class: ADD method: import org.junit.Assert; import org.junit.Test; public class CalculatorTest { @Test public void testAdd() { Calculator calculator = new Calculator(); int result = calculator.add(2, 3); Assert.assertEquals(5, result); } } In the above example, we first introduced Junit's Assert class and test annotations.Then, we created a test class called CalculatorTest and defined a test method called Testadd in the class.In this method, we created a Calculator object, calling its ADD method, and then using the Assert class assertequals method to verify whether the actual results are equal to the expected result. After writing the test class, we can use the Junit operator to perform the test.Junit provides several different operators, such as the Default Runner and Parameterized Runner in Junit 4.Developers can choose the right operator to perform the test as needed. The Junit interface framework in the Java library has ended here.By following the above steps, developers can easily use Junit to write and execute unit tests to ensure the correctness of the Java class library's methods and functions.