mockito模拟依赖注入

Mockito @InjectMocks annotations allow us to inject mocked dependencies in the annotated class mocked object. This is useful when we have external dependencies in the class we want to mock. We can specify the mock objects to be injected using @Mock or @Spy annotations.

Mockito @InjectMocks批注允许我们将模拟的依赖项注入到带注释的类模拟对象中。 当我们要模拟的类中具有外部依赖项时，这很有用。 我们可以使用@Mock或@Spy批注指定要注入的模拟对象。

Mockito @InjectMocks (Mockito @InjectMocks)

Mockito tries to inject mocked dependencies using one of the three approaches, in the specified order.

Mockito尝试使用三种方法之一以指定的顺序注入模拟的依赖项。

1. Constructor Based Injection – when there is a constructor defined for the class, Mockito tries to inject dependencies using the biggest constructor.基于构造函数的注入–当为该类定义了构造函数时，Mockito尝试使用最大的构造函数注入依赖项。
2. Setter Methods Based – when there are no constructors defined, Mockito tries to inject dependencies using setter methods.基于Setter方法-当未定义构造函数时，Mockito尝试使用setter方法注入依赖项。
3. Field Based – if there are no constructors or field-based injection possible, then mockito tries to inject dependencies into the field itself.基于字段的–如果没有可能的构造函数或基于字段的注入，则Mockito尝试将依赖项注入字段本身。

If there is only one matching mock object, then mockito will inject that into the object. If there is more than one mocked object of the same class, then mock object name is used to inject the dependencies.

如果只有一个匹配的模拟对象，则模拟将把它注入到对象中。 如果同一类的模拟对象不止一个，则使用模拟对象名称来注入依赖项。

模拟@InjectMocks示例 (Mock @InjectMocks Example)

Let’s create some services and classes with dependencies so that we can see Mockito dependency injection of mocks in action.

让我们创建一些具有依赖项的服务和类，以便我们可以看到Mockito依赖项在模拟中的依赖注入。

Service Classes

服务等级

package com.journaldev.injectmocksservices;public interface Service {public boolean send(String msg);
}

package com.journaldev.injectmocksservices;public class EmailService implements Service {@Overridepublic boolean send(String msg) {System.out.println("Sending email");return true;}}

package com.journaldev.injectmocksservices;public class SMSService implements Service {@Overridepublic boolean send(String msg) {System.out.println("Sending SMS");return true;}
}

App Service Classes with Dependencies

具有依赖关系的App Service类

package com.journaldev.injectmocksservices;//For Constructor Based @InjectMocks injection
public class AppServices {private EmailService emailService;private SMSService smsService;public AppServices(EmailService emailService, SMSService smsService) {this.emailService = emailService;this.smsService = smsService;}public boolean sendSMS(String msg) {return smsService.send(msg);}public boolean sendEmail(String msg) {return emailService.send(msg);}
}

package com.journaldev.injectmocksservices;//For Property Setter Based @InjectMocks injection
public class AppServices1 {private EmailService emailService;private SMSService smsService;public void setEmailService(EmailService emailService) {this.emailService = emailService;}public void setSmsService(SMSService smsService) {this.smsService = smsService;}public boolean sendSMS(String msg) {return smsService.send(msg);}public boolean sendEmail(String msg) {return emailService.send(msg);}}

package com.journaldev.injectmocksservices;//For Field Based @InjectMocks injection
public class AppServices2 {private EmailService emailService;private SMSService smsService;public boolean sendSMS(String msg) {return smsService.send(msg);}public boolean sendEmail(String msg) {return emailService.send(msg);}}

@InjectMocks构造函数注入示例 (@InjectMocks Constructor Injection Example)

package com.journaldev.mockito.injectmocks;import static org.junit.jupiter.api.Assertions.*;
import static org.mockito.Mockito.*;import org.junit.jupiter.api.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;import com.journaldev.injectmocksservices.AppServices;
import com.journaldev.injectmocksservices.AppServices1;
import com.journaldev.injectmocksservices.AppServices2;
import com.journaldev.injectmocksservices.EmailService;
import com.journaldev.injectmocksservices.SMSService;class MockitoInjectMocksExamples extends BaseTestCase {@Mock EmailService emailService;@Mock SMSService smsService;@InjectMocks AppServices appServicesConstructorInjectionMock;@InjectMocks AppServices1 appServicesSetterInjectionMock;@InjectMocks AppServices2 appServicesFieldInjectionMock;@Testvoid test_constructor_injection_mock() {when(appServicesConstructorInjectionMock.sendEmail("Email")).thenReturn(true);when(appServicesConstructorInjectionMock.sendSMS(anyString())).thenReturn(true);assertTrue(appServicesConstructorInjectionMock.sendEmail("Email"));assertFalse(appServicesConstructorInjectionMock.sendEmail("Unstubbed Email"));assertTrue(appServicesConstructorInjectionMock.sendSMS("SMS"));}
}

Did you noticed that my test class is extending BaseTestCase. This is to initialize Mockito mocks before the tests, here is the code of the class.

您是否注意到我的测试类正在扩展BaseTestCase 。 这是在测试之前初始化Mockito模拟，这是该类的代码。

package com.journaldev.mockito.injectmocks;import org.junit.jupiter.api.BeforeEach;
import org.mockito.MockitoAnnotations;class BaseTestCase {@BeforeEachvoid init_mocks() {MockitoAnnotations.initMocks(this);}}

If you won’t call MockitoAnnotations.initMocks(this); then you will get NullPointerException.

如果您不致电MockitoAnnotations.initMocks(this); 那么您将获得NullPointerException 。

Also, I am using JUnit 5 to run the test cases. If you are not familiar with it, have a look at JUnit 5 Tutorial.

另外，我正在使用JUnit 5运行测试用例。 如果您不熟悉它，请查看JUnit 5 Tutorial 。

@InjectMocks设置器方法注入示例 (@InjectMocks Setter Methods Injection Example)

@Test
void test_setter_injection_mock() {when(appServicesSetterInjectionMock.sendEmail("New Email")).thenReturn(true);when(appServicesSetterInjectionMock.sendSMS(anyString())).thenReturn(true);assertTrue(appServicesSetterInjectionMock.sendEmail("New Email"));assertFalse(appServicesSetterInjectionMock.sendEmail("Unstubbed Email"));assertTrue(appServicesSetterInjectionMock.sendSMS("SMS"));}

@InjectMocks基于字段的注入示例 (@InjectMocks Field Based Injection Example)

@Test
void test_field_injection_mock() {when(appServicesFieldInjectionMock.sendEmail(anyString())).thenReturn(true);when(appServicesFieldInjectionMock.sendSMS(anyString())).thenReturn(true);assertTrue(appServicesFieldInjectionMock.sendEmail("Email"));assertTrue(appServicesFieldInjectionMock.sendEmail("New Email"));assertTrue(appServicesFieldInjectionMock.sendSMS("SMS"));}

Reference: API Doc

参考： API文档

翻译自: https://www.journaldev.com/21887/mockito-injectmocks-mocks-dependency-injection

mockito模拟依赖注入