Mockito 验证方法的实战应用

t0_54manong

于 2025-03-01 01:43:12 发布

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文章标签： log4j 个人开发

本文链接：https://blog.youkuaiyun.com/m0_74337424/article/details/145941402

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在软件开发中，单元测试是确保代码质量的重要环节。Mockito 是一个流行的 Java 模拟框架，它可以帮助我们轻松地创建和验证模拟对象的行为。本文将通过一个具体的实例，展示如何使用 Mockito 的 verify 方法来验证模拟对象的方法调用。

一、Mockito 的 `verify` 方法

Mockito 提供了强大的功能来验证模拟对象的方法是否被调用，以及调用时的参数是否符合预期。Mockito#verify(T mock) 方法用于确认特定的交互是否发生。换句话说，它可以帮助我们验证模拟对象的方法是否被正确调用。

二、实例应用

1. 示例应用代码

首先，我们定义一个简单的接口 MyService 和一个类 MyProcessor，用于演示如何使用 Mockito 验证方法调用。

package com.logicbig.example;

public interface MyService {
    public int doSomething(String processName);
}

package com.logicbig.example;

public class MyProcessor {
    private String processName;
    private MyService myService;

    public MyProcessor(String processName, MyService myService) {
        this.processName = processName;
        this.myService = myService;
    }

    public void process() {
        int returnInteger = processName != null ? myService.doSomething(processName) : -1;
        System.out.println("My Integer is: " + returnInteger);
    }
}

2. 测试代码

接下来，我们编写一个测试类 ProcessorTest，使用 Mockito 来验证 MyService 的 doSomething 方法是否被正确调用。

package com.logicbig.example;

import org.junit.Test;
import org.mockito.Mockito;

public class ProcessorTest {
    @Test
    public void processTest() {
        MyService myService = Mockito.mock(MyService.class);
        String processName = "dummy-process-name";
        Mockito.when(myService.doSomething(processName)).thenReturn(10);

        MyProcessor myProcessor = new MyProcessor(processName, myService);
        myProcessor.process();

        Mockito.verify(myService).doSomething(processName);
    }
}

3. 测试运行结果

运行上述测试代码，Maven 的输出如下：

[INFO] Scanning for projects...
[INFO]
[INFO] ---------< com.logicbig.example:mockito-verify-method-example >---------
[INFO] Building mockito-verify-method-example 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ mockito-verify-method-example ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ mockito-verify-method-example ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ mockito-verify-method-example ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ mockito-verify-method-example ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ mockito-verify-method-example ---
-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.logicbig.example.ProcessorTest
My Integer is: 10
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.732 sec
Results :
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  3.671 s
[INFO] Finished at: 2020-07-23T00:08:57-05:00
[INFO] ------------------------------------------------------------------------

从输出结果可以看出，测试成功通过，MyService 的 doSomething 方法被正确调用。

4. 验证失败的情况

如果我们将测试代码中的 processName 设置为 null，模拟对象的 doSomething 方法将不会被调用。此时，测试将失败。

package com.logicbig.example;

import org.junit.Test;
import org.mockito.Mockito;

public class ProcessorTest2 {
    @Test
    public void processTest() {
        MyService myService = Mockito.mock(MyService.class);
        String processName = null;
        Mockito.when(myService.doSomething(processName)).thenReturn(10);

        MyProcessor myProcessor = new MyProcessor(processName, myService);
        myProcessor.process();

        Mockito.verify(myService).doSomething(processName);
    }
}

运行上述测试代码，Maven 的输出如下：

[INFO] Scanning for projects...
[INFO]
[INFO] ---------< com.logicbig.example:mockito-verify-method-example >---------
[INFO] Building mockito-verify-method-example 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ mockito-verify-method-example ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ mockito-verify-method-example ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ mockito-verify-method-example ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ mockito-verify-method-example ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ mockito-verify-method-example ---
-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.logicbig.example.ProcessorTest2
My Integer is: -1
Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 1.055 sec <<< FAILURE!
processTest(com.logicbig.example.ProcessorTest2)  Time elapsed: 0.916 sec  <<< FAILURE!
Wanted but not invoked:
myService.doSomething(null);
-> at com.logicbig.example.ProcessorTest2.processTest(ProcessorTest2.java:16)
Actually, there were zero interactions with this mock.

从输出结果可以看出，测试失败，因为 MyService 的 doSomething 方法没有被调用。