Junit Jupiter's key technical principles analysis of key technical principles in the Java library
Junit Jupiter's key technical principles analysis of key technical principles in the Java library
Summary: Junit Jupiter (polymer) framework is a Java class library for writing unit testing. Compared with the early version of the Junit framework, the Jupiter framework provides more functions and flexibility.This article will analyze the key technical principles of the Junit Jupiter framework and provide the corresponding Java code example.
1 Introduction
Unit test is a key link in the process of software development, which can help developers verify the correctness and reliability of each functional module.Junit is a widely used Java unit testing framework, while Junit Jupiter is a new framework introduced by Junit 5. It uses the new features of Java 8 to provide more powerful and flexible functions.
2. Comment Driven Test
Junit Jupiter framework is based on annotations. Developers can use different annotations to define test methods, front conditions, rear conditions, etc.The following is a simple example:
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
public class MyTests {
@Test
void additionTest() {
int result = 2 + 2;
assertEquals(4, result);
}
}
In the above code, `@test` annotations are used to identify a test method, and the method of` assertequals` is used to verify whether the calculation results meet the expectations.By annotation drive, we can easily define and execute various test cases.
3. Parameterization test
The Junit Jupiter framework introduces the concept of parameterized testing, allowing us to provide different input parameters through the annotation as a test method, and verify whether its output results meet the expectations.The following is an example:
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.ValueSource;
import static org.junit.jupiter.api.Assertions.assertTrue;
public class MyTests {
@ParameterizedTest
@ValueSource(strings = { "hello", "world" })
void lengthTest(String str) {
assertTrue(str.length() > 0);
}
}
In the above code, the annotation of `@Parameterizedtest` identifies a parameterized test method, and` `@` `` `` `` `annotations of the annotations provide multiple input parameters.Through parameterized testing, we can effectively reduce the repeat code and verify the behavior and output of different inputs.
4. Extension model
Junit Jupiter's framework introduces the concept of extended models. By achieving the corresponding interface or annotation, we can customize test classes, test methods, test life cycles, etc.The following is an example of a custom test class:
import org.junit.jupiter.api.extension.ExtendWith;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
@ExtendWith(MyExtension.class)
public class MyTests {
@Test
void customTest() {
String name = "JUnit";
assertEquals(5, name.length());
}
}
In the above code, the annotation of `@extendwith` is used to specify the implementation class of the custom test class extension.By expanding the model, we can achieve more accurate test control and management.
5. Test the life cycle
The Junit Jupiter framework introduces the concept of testing cycle, which can control the initialization and destruction of testing methods and test methods.The following is an example of a test life cycle:
import org.junit.jupiter.api.*;
import static org.junit.jupiter.api.Assertions.assertTrue;
@TestInstance(TestInstance.Lifecycle.PER_CLASS)
public class MyTests {
@BeforeAll
void init() {
System.out.println("Initializing...");
}
@BeforeEach
void setup() {
System.out.println("Setting up...");
}
@Test
void test1() {
assertTrue(true);
}
@Test
void test2() {
assertTrue(true);
}
@AfterEach
void tearDown() {
System.out.println("Tearing down...");
}
@AfterAll
void cleanup() {
System.out.println("Cleaning up...");
}
}
In the above code, the life cycle of the test instance is specified through the annotation of `@Testinstance`; the annotations of the test class are specified through the`@befaceall` and@afterrall annotations, and the `@beForeeach` and`@Afterreach` annotations are used for the initialization and destruction of each test method, respectively.
Summarize:
The Junit Jupiter framework is a Java class library for writing unit testing. The key technical principles are used in the Java class library, such as annotation driver testing, parameterized testing, expansion models, and test life cycles.By using the Junit Jupiter framework, developers can write and perform unit testing more convenient, flexibly and efficiently.You can obtain more details and documents on the Junit Jupiter framework from the official website of Junit (https://junit.org/junit5/).
