The best practice to test using the Mockito JUNIT JUPITER framework

Mockito and JUnit Jumpiter framework are two popular tools for unit testing in Java.Mockito is used to create and manage simulated objects, and the Junit Jupiter framework is used to write and run test cases.In this article, we will explore the best practice of testing using Mockito and Junit Jupiter frameworks. 1. Basic principles of unit testing: -The test independence: Make sure that each test case is independent and is not affected by other test cases. -The comprehensiveness: try to overwrite the possible test scenes, including normal and abnormal conditions. -E repeatability and verification: The test results should be repeated and can verify whether it meets the expectations. 2. Introduce Mockito and Junit Jupiter dependencies: Add Mockito and Junit Jupiter to the project's construction file.For example, the project built using Maven can add the following dependencies: <dependencies> <dependency> <groupId>org.mockito</groupId> <artifactId>mockito-core</artifactId> <version>x.x.x</version> <scope>test</scope> </dependency> <dependency> <groupId>org.junit.jupiter</groupId> <artifactId>junit-jupiter-api</artifactId> <version>x.x.x</version> <scope>test</scope> </dependency> </dependencies> 3. Create a test class and test method: -In the test method in the test class. -Ad using the `@mock` annotation to create an object that needs to be simulated. -Su using `@injectmocks` annotations to inject the simulation object into the tested object. import org.junit.jupiter.api.Test; import org.junit.jupiter.api.extension.ExtendWith; import static org.mockito.Mockito.*; import org.mockito.Mock; import org.mockito.InjectMocks; import org.mockito.junit.jupiter.MockitoExtension; @ExtendWith(MockitoExtension.class) public class MyServiceTest { @Mock private MyDependency myDependency; @InjectMocks private MyService myService; @Test public void testDoSomething() { // The behavior of simulation MyDependency when(myDependency.someMethod()).thenReturn("mocked value"); // Execute the test method String result = myService.doSomething(); // Verification results meet the expectations assertEquals("expected value", result); // Verify myDependency.somemethod () whether it has been called verify(myDependency, times(1)).someMethod(); } } 4. Use mockito to simulate and verify: -Ad the method of using `when (obj.method ()). The thenreturn (value) to simulate the object and return the specified value. -Ad the method of using `Verify (Obj, Times (N)). Method () to verify whether the object is called to the specified number of times. 5. Run test: Run the test class or use the construction tool such as Maven to run all test cases in the IDE. 6. Use the appropriate assertion method: The Junit Jupiter framework provides a variety of ways of assertion, such as `Assertequals`,` Assertnotnull`, `AssertthRows`, etc.Select the appropriate assertion method to verify whether the test results meet the expectations. Summarize: Using Mockito and JUNIT JUPITER frameworks can be easily tested by unit testing, and ensure the independence, comprehensiveness and verification of the test cases.Through the simulation and verification function of Mockito, the behavior of the code can accurately verify whether the code is in line with expectations.Applying these best practices to test code can greatly improve the quality and reliability of testing.