Junit Jupiter's technical principle analysis of technical principles in the Java class library

Junit Jupiter's technical principle analysis of technical principles in the Java class library Junit Jupiter is a Java test framework for writing and executing automated testing.It is part of Junit 5, providing developers with a set of powerful and flexible testing tools.This article will analyze the technical principles of the Junit Jupiter framework in the Java class library and provide some Java code examples. 1. Introduce junit jupiter dependencies Before the beginning, we need to introduce Junit Jupiter's dependence in our Java project.We can add dependencies through Maven or Gradle construction tools.The following is the example code of Maven: <dependency> <groupId>org.junit.jupiter</groupId> <artifactId>junit-jupiter-api</artifactId> <version>5.8.0</version> <scope>test</scope> </dependency> 2. Write junit jupiter test case Test cases written in Junit Jupiter start with `@test` annotations.Junit Jupiter provides many annotations and assertions to help us write and organize testing.The following is a simple example: import org.junit.jupiter.api.Assertions; import org.junit.jupiter.api.Test; public class MyTest { @Test void additionTest() { int result = 2 + 2; Assertions.assertEquals(4, result); } } In the above example, we use the@test` annotation to mark the method of the adDitiontest` as a test method.This method executes a simple way to add operation and uses `Assertions.assertequals ()` to assert whether the calculation result is equal to the expected value. 3. Run junit jupiter test The Junit Jupiter test can run through various ways, including command line tools, integrated development environments (IDE), and continuous integration (CI) tools.In most cases, we can use Gradle or Maven to run the test.The following is an example command that runs Junit Jupiter test by Maven: shell mvn test 4. Junit Jupiter's technical principles The core principle of Junit Jupiter is Java -based reflex mechanism and annotation processing.When we use a method to mark the `@test` annotation, Junit Jupiter's engine will use the reflection mechanism to resolve our test and test methods.It will check whether the annotation of `@test` exists and perform the corresponding test logic. Junit Jupiter also provides some other annotations, such as `@beforeeach`,@afterreach`,` `@beForeall` and`@asfterall, etc., for performing some preparations and cleaning operations before and after each test method. The core engine of Junit Jupiter can also be extended by adding custom extensions.These extensions can be used to add additional assertions, test life cycle callbacks or custom test behaviors.JUNIT JUPITER architecture is friendly and scalable, enabling developers to flexibly customize according to project needs. Summarize: Junit Jupiter is a powerful and flexible Java testing framework. By using the principle of reflection and annotation, the Java class library can be automated.It provides rich annotations and assertions, as well as expansion mechanisms, so that developers can easily write and manage test cases.I hope this article will help you understand the technical principles of the Junit Jupiter framework in the Java class library.