The technical principles of the Junit Vintage Engine framework in the Java class library

Detailed explanation of the technical principles of Junit Vintage Engine framework in Java Library Junit Vintage Engine is a framework introduced in Junit 4, which aims to be compatible with test cases compatible with Junit 3.This article will explain the technical principles of the Junit Vintage Engine framework and how to use it in the Java library. 1 Overview Junit Vintage Engine allows us to perform test cases of Junit 3 in Junit 4's test environments.This is very useful for those projects that have not yet moved to JUnit 4.Junit Vintage Engine uses the adapter mode to pack the test code of Junit 3 into a form in line with Junit 4, so as to ensure that the test cases of Junit 3 can be performed normally in the Junit 4 environment. 2. Technical principles The core principle of Junit Vintage Engine is the adapter mode.This mode converts the original Junit 3 test case into the Junit 4 test case through the wrapper class.The adapter mode allows Junit Vintage Engine to combine the test case of Junit 3 into the test framework of Junit 4 without modifying the original code. In Junit Vintage Engine, the adapter class is called JunitvintageTestadapter.It implements the Test interface of Junit 4 and entrusts it to the TestCase class of Junit 3.JunitvintageTestadapter uses the Junit 3 test case class as a parameter to create an instance within its internal.Then, when the test engine of Junit 4 calls the TEST interface method of JunitvintageTestAdapter, the adapter will forward the Junit 3 test case objects that call the bottom layer of the bottom layer. The following is an example code that demonstrates how to use Junit Vintage Engine to run Junit 3 test cases in the Java class library: import junit.framework.Test; import junit.framework.TestSuite; import org.junit.runner.JUnitCore; import org.junit.runner.Result; public class JUnit3RunnerExample { public static void main(String[] args) { // Create testsuite and add the test case class of Junit 3 to the test kit TestSuite suite = new TestSuite(); suite.addTestSuite(OldTestClass1.class); suite.addTestSuite(OldTestClass2.class); // Create Junit Vintage Engine adapter Test junit3Tests = new JUnit4TestAdapter(suite); // Create and run JUNIT 4 test engine JUnitCore junit4 = new JUnitCore(); Result result = junit4.run(junit3Tests); // Process test results System.out.println("Tests run: " + result.getRunCount()); System.out.println("Tests failed: " + result.getFailureCount()); } } In the above example, we first created a testsuite object and added a test case class of Junit 3 to it.Then, we created a Junit Vintage Engine adapter and passed the testsuite object as a parameter.Finally, we use Junitcore to run Junit 4 test engines and process the test results. Summarize: This article explains the technical principles of the Junit Vintage Engine framework and how to use it in the Java library.By using the adapter mode, Junit Vintage Engine allows us to perform the test case of Junit 3 in the Junit 4 test environment to achieve backward compatibility.I hope this article can help you understand the working principle of Junit Vintage Engine.