Mockito 示例中的 verify() 方法-java教程-PHP中文网

Mockito 中的 verify() 方法用于确认与模拟对象发生了特定的交互。当您想要确保在代码执行期间使用特定参数调用某个方法时，这在测试中特别有用。

下面是一个具有服务和控制器层的 Spring Boot 应用程序示例，其中在测试中使用了 verify() 方法。

使用 Spring Web 依赖项创建 Spring Boot Starter 项目并执行以下示例

verify() method in Mockito example

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
 <modelVersion>4.0.0</modelVersion>
 <parent>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-parent</artifactId>
  <version>3.4.1</version>
  <relativePath/> <!-- lookup parent from repository -->
 </parent>
 <groupId>com.example</groupId>
 <artifactId>VerifySpringBootExample</artifactId>
 <version>0.0.1-SNAPSHOT</version>
 <name>VerifySpringBootExample</name>
 <description>Demo project for Spring Boot</description>
 <url/>
 <licenses>
  <license/>
 </licenses>
 <developers>
  <developer/>
 </developers>
 <scm>
  <connection/>
  <developerConnection/>
  <tag/>
  <url/>
 </scm>
 <properties>
  <java.version>17</java.version>
 </properties>
 <dependencies>
  <dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-web</artifactId>
  </dependency>

  <dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-test</artifactId>
   <scope>test</scope>
  </dependency>
 </dependencies>

 <build>
  <plugins>
   <plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
   </plugin>
  </plugins>
 </build>

</project>

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Spring Boot 应用
员工.java

package com.example.demo.model;

public class Employee {
    private String id;
    private String name;

    // Constructor, Getters, and Setters
    public Employee(String id, String name) {
        this.id = id;
        this.name = name;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

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EmployeeService.java

package com.example.demo.service;

import com.example.demo.model.Employee;
import org.springframework.stereotype.Service;

@Service
public class EmployeeService {
    public void saveEmployee(Employee employee) {
        // Business logic to save the employee (e.g., in a database)
        System.out.println("Employee saved: " + employee.getName());
    }
}

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EmployeeController.java

package com.example.demo.controller;

import com.example.demo.model.Employee;
import com.example.demo.service.EmployeeService;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class EmployeeController {
    private final EmployeeService employeeService;

    public EmployeeController(EmployeeService employeeService) {
        this.employeeService = employeeService;
    }

    @PostMapping("/employees")
    public void saveEmployee(@RequestBody Employee employee) {
        employeeService.saveEmployee(employee);
    }
}

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使用 Mockito 进行 JUnit 测试
EmployeeControllerTest.java

package com.example.demo.controller;

import com.example.demo.model.Employee;
import com.example.demo.service.EmployeeService;
import org.junit.jupiter.api.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;

import static org.mockito.Mockito.*;

class EmployeeControllerTest {

    @Mock
    private EmployeeService employeeService;

    @InjectMocks
    private EmployeeController employeeController;

    public EmployeeControllerTest() {
        MockitoAnnotations.openMocks(this); // Initialize mocks
    }

    @Test
    void testSaveEmployee() {
        // Arrange
        Employee employee = new Employee("1", "John Doe");

        // Act
        employeeController.saveEmployee(employee);

        // Assert
        // Verify that the saveEmployee method was called once with the correct argument
        verify(employeeService, times(1)).saveEmployee(employee);
    }
}

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说明

用 @Mock 进行嘲笑：

EmployeeService 是模拟的，这意味着它的行为可以在不依赖于实际实现的情况下进行控制。

使用 @InjectMocks 注入模拟：

EmployeeController 使用模拟的 EmployeeService。

verify() 方法：

确认使用指定的 Employee 对象调用了模拟的 EmployeeService 的 saveEmployee() 方法一次。

确保该方法被调用一次。其他选项如 never() 或 atLeastOnce() 可用于不同的验证需求。

为什么 verify() 有用？

确保预期的交互：确认测试的逻辑按预期与依赖组件进行交互。

防止过度调用：确保方法调用次数不会超过必要的次数，这可能会突出显示冗余或不需要的逻辑。