The technical principles of Junit Platform Launcher in the Java class library

The Junit platform operator is an important component in the Junit 5 framework for performing and managing test cases.It provides a scalable platform that can be used to run different test engines and generate test reports.This article will introduce the technical principles of the Junit platform operator and provide some Java code examples. The technical principles of the Junit platform operator are as follows: 1. Introduce test engine: Junit platform operator dynamically loads the test engine by using the ServiceLoader mechanism.The test engine is a specific test framework and is responsible for actual test cases.Common test engines include the Junit Vintage engine, the Junit Jupiter engine, and other custom engines.Use the ServiceLoader mechanism to load the test engine to achieve flexible scalability. 2. Find the test class: The operator searches and finds the test class through the reflection mechanism of Java.It finds test methods and classes marked by @Test annotation and builds testing programs. 3. Execute test case: The test plan contains all test cases to be executed.The operator executes test cases one by one by calling the API provided by the test engine and obtained the test results.The test engine is responsible for specific execution logic, such as creating test instances, calling test methods, and processing abnormalities. 4. Generate test report: The test results were collected and stored by the Junit platform operator.According to the user's configuration, the test operator can generate various forms of test reports, such as text files, HTML reports, or XML reports. Below is a simple example code that shows how to use the Junit 5 platform operator to perform test cases: import org.junit.platform.launcher.Launcher; import org.junit.platform.launcher.LauncherDiscoveryRequest; import org.junit.platform.launcher.core.LauncherFactory; import org.junit.platform.launcher.listeners.SummaryGeneratingListener; import org.junit.platform.launcher.listeners.TestExecutionSummary; public class JUnitLauncherExample { public static void main(String[] args) { // Create an operator Launcher launcher = LauncherFactory.create(); // Create a test discovery request LauncherDiscoveryRequest request = LauncherDiscoveryRequestBuilder.request() .selectors(selectClass(MyTestClass.class)) .build(); // Create the test result collector SummaryGeneratingListener listener = new SummaryGeneratingListener(); // Run the test launcher.registerTestExecutionListeners(listener); launcher.execute(request); // Get the test results TestExecutionSummary summary = listener.getSummary(); System.out.println ("A total of" + Summary.Gettestsfoundcount () + "" individual test case "); System.out.println ("Successfully run" + Summary.GetTestSuccededCount () + "() +" () "); System.out.println ("The failure runs" + Summary.Gettestsfailedcount () + "" individual test case "); } } class MyTestClass { @Test void testExample() { // Test logic assertEquals(2, 1 + 1); } } In the above example code, we run the test by creating a Junit platform operator (Launcher) object, and then specify the test class to be executed.The operator will perform test cases through the test engine and collect the running results.Finally, we obtained the abstract information of execution through the SummaryGeneratingListener and exported it to the console.