Reveal the technical principles of the Junit platform operator in the Java class library
Reveal the technical principles of the Junit platform operator in the Java class library
Junit is one of the unit testing frameworks widely used in Java development. Among them, the Junit platform operator is one of the core components of the Junit framework.This article will explore the technical principles of the Junit platform operator to help readers understand their internal mechanisms and how to use and expand it.
1. Junit platform overview
Junit platform is a new platform introduced by Junit 5 and one of the core components of the Junit framework.The Junit platform provides a modular -based test engine and operator, as well as some auxiliary tools for performing and managing testing.The design goal of the Junit platform is to provide a flexible and scalable test platform that allows developers to use various programming languages and different testing tools.
2. Junit platform operator
The Junit platform operator is an important component of the Junit platform, which is responsible for loading, executing and managing testing cases.It is a class that implements the `Launcher` interface to control the entire test execution process.Junit platforms predetermine several commonly used operators, such as `Consolelauncher` and` Intellijlauncher`, but can also customize operators to meet specific test needs.
3. Loading and initialization of the operator
The Junit platform will load all available operators through Java's `ServiceLoader` mechanism.This means that developers can expand the functions of the Junit platform by adding new operators to the class path.After loading, the Junit platform will instantiate an `Testengine` object for each operator, which is responsible for subsequent test execution and results reports.
4. Test discovery and execution
An important function of the Junit platform operator is the discovery and execution of testing.According to the specified search strategy, the operator finds all test cases and encapsulates it as an object of `TestDescriptor.The operator then builds a testing tree based on the dependency relationship of the test case, and calls the corresponding `Testengine` to perform the test.During the execution, the operator has effectively managed the parallel execution and failure of the test.
5. Collection and report of test results
Junit platform operator is responsible for collecting test results and generating corresponding test reports.When the test execution is completed, the operator will call the method defined in the interface of the `TestexecutionListener` interface, and pass the test results to the registered monitor.Developers can customize the monitor to handle the test results, such as generating HTML reports, sending notifications, etc.
Below is a simple example, demonstrating how to customize a Junit platform operator:
import org.junit.platform.launcher.Launcher;
import org.junit.platform.launcher.LauncherDiscoveryRequest;
import org.junit.platform.launcher.TestExecutionListener;
import org.junit.platform.launcher.TestIdentifier;
import org.junit.platform.launcher.core.LauncherDiscoveryRequestBuilder;
import org.junit.platform.launcher.core.LauncherFactory;
public class MyCustomRunner {
public static void main(String[] args) {
LauncherDiscoveryRequest request = LauncherDiscoveryRequestBuilder.request()
.selectors(selectClass(MyTestClass.class))
.build();
Launcher launcher = LauncherFactory.create();
TestExecutionListener listener = new MyCustomListener();
launcher.registerTestExecutionListeners(listener);
launcher.execute(request);
}
static class MyTestClass {
// Test definition ...
}
static class MyCustomListener implements TestExecutionListener {
// The implementation code of the listener ...
}
}
Through the above examples, we can see that the key to customized Junit platform opera is to build a test request `LauncherDiscoveryRequest`, register a monitor and perform testing.In this way, we can expand the functions of the Junit platform according to our needs, so as to better test unit testing.
Summary: The Junit platform operator is one of the core components of the Junit framework, which is responsible for loading, executing and managing testing cases.Its technical principles include loading and initialization of operators, discovery and execution of testing, and collection and reports of test results.By customized the Junit platform operator, you can meet specific test needs and improve the efficiency and flexibility of unit testing.
