Introduction to the technical principles of Junit Jupiter (polymer) framework in the Java class library
Junit Jupiter is part of the Junit 5 framework. It provides a set of powerful tools and functions to test the functions and performance of the Java program.JUNIT JUPITER's technical principles involve the following aspects:
1. Note driver: Junit just user uses annotations to define test classes and test methods.It provides some commonly used annotations, such as@test,@beforeeach,@afterreach, etc., for label testing methods and test classes.These annotations tell Junit Jupiter what methods to perform and provide corresponding test context.
The following is a sample test class:
import org.junit.jupiter.api.Test;
public class MyTestClass {
@Test
void myTestMethod() {
// The code of the test method
}
}
2. Extension model: Junit Jupiter introduced the extension model, allowing developers to be able to define the test execution process by achieving the expansion interface.Extended interfaces include TestexecutionExceptionhandler, TestinStancepostProcessor, Testwatcher, etc.Developers can implement these interfaces to define abnormal treatment, instantiated treatment or test observation.
The following is an example of using Testwatcher extension interface:
import org.junit.jupiter.api.extension.ExtendWith;
import org.junit.jupiter.api.extension.TestWatcher;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtensionContext;
@ExtendWith(MyTestWatcher.class)
public class MyTestClass {
@Test
void myTestMethod() {
// The code of the test method
}
}
class MyTestWatcher implements TestWatcher {
@Override
public void testSuccessful(ExtensionContext context) {
// Treatment logic after testing
}
@Override
public void testFailed(ExtensionContext context, Throwable cause) {
// Test logic after test failure
}
}
3. Abstract library: JUNIT JUPITER allows developers to use various assertion libraries to write assertive sentences to verify whether the expected results and actual results are consistent.Junit Jupiter provides its own assertion library, such as the Assertions class, which includes some common assertions, such as Assertequals, Asserttrue, AssertFalse, etc.In addition, developers can also expand the assertion function by introducing other assertions, such as Assertj and Hamcrest.
The following is an example of using Junit Jupiter with an assertion library:
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
public class MyTestClass {
@Test
void myTestMethod() {
String str = "JUnit";
assertEquals(5, str.length());
}
}
4. Parameterization test: Junit Jupiter supports parameterization test, allows developers to run the same test method on multiple sets of input data and collect the results of each test.By using @parameterizedtest annotations and @Valuesource annotations, developers can easily achieve parameterized testing.
The following is an example of a parameterized test:
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.ValueSource;
import static org.junit.jupiter.api.Assertions.assertTrue;
public class MyTestClass {
@ParameterizedTest
@ValueSource(ints = {1, 2, 3})
void myTestMethod(int number) {
assertTrue(number > 0);
}
}
Through the above technical principles, Junit Jupiter provides developers with a flexible and scalable test framework, making the writing and running tests more simple and efficient.Whether it is traditional unit testing or advanced functional and performance testing, Junit Jupiter is one of the indispensable tools for Java developers.
