The technical principles of the Junit Vintage Engine framework in the Java class library
Junit Vintage Engine (hereinafter referred to as Vintage Engine) is a sub -module of the Junit 5 framework. It provides the ability to seamlessly migrate the test code of Junit 3 and Junit 4 to the Junit 5 platform.This article will introduce the technical principles of the Vintage Engine framework in the Java class library in detail.
1. Overview of Vintage Engine framework
Vintage Engine is part of the Junit 5 framework, which aims to retain and support the old version of the Junit API.It allows developers to continue running the old version of the test code while migrating to Junit 5 to gradually upgrade and improve the test kit.
2. The core principle of Vintage Engine
The core principles of Vintage Engine are very simple and clear. It implements test execution by converting the test code of Junit 3 and Junit 4 to the corresponding Junit 5 code.Below is the main technical principle of Vintage Engine:
1. The bridge of junit 3
For the Junit 3 test kit, Vintage Engine uses the Junit3adapter adapter to connect its bridge to the Junit 5 test engine.Junit3adapter implements Testengine interface, responsible for performing test cases of Junit 3, and converting the result to a test report of Junit 5.
2. Extension of junit 4
For the Junit 4 test kit, Vintage Engine adds Junit 4's test framework into the test engine of Junit 5 through the Junit4tetengine extension.Junit4tetengine is responsible for loading the JUNIT 4 test kit and acting for its execution to convert the result to the Junit 5 test report.
3. Test code conversion
In order to enable the Junit 4 test code to correctly execute in the Junit 5 engine, Vintage Engine also needs to convert Junit 4's annotations and assertions into the corresponding Junit 5 annotation and assertion.For example, convert the @test annotation of junit 4 to the@organit.jupiter.api.test annotation of junit 5.
3. Example
The following is a simple example that demonstrates how to use Vintage Engine to execute a Junit 4 test kit:
import org.junit.Test;
import static org.junit.Assert.assertEquals;
public class MyTestClass {
@Test
public void testAddition() {
int result = 2 + 2;
assertEquals(4, result);
}
}
Suppose the above code is a test kit based on Junit 4.Now, we will use Vintage Engine to perform the test kit test method:
import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;
public class VintageEngineExample {
public static void main(String[] args) {
Result result = JUnitCore.runClasses(MyTestClass.class);
if (result.wasSuccessful()) {
System.out.println("All tests passed!");
} else {
System.out.println("Some tests failed:");
for (Failure failure : result.getFailures()) {
System.out.println(failure.toString());
}
}
}
}
In the above example, we use Junitcore to run the test method of Mytestclass and output the corresponding information based on the test results.Vintage Engine will automatically convert Junit 4's assertions and annotations to the corresponding Junit 5 code during running.
Through the above examples, we can see the execution process of Vintage Engine and its technical principles in the Java library.
in conclusion
Through the Vintage Engine framework, we can easily migrate the test code based on Junit 3 and Junit 4 to the Junit 5 platform.With Vintage Engine, we can gradually upgrade the test kit and enjoy the new features and improvements brought by Junit 5.
