如何从应用程序中加载属性

Question

我正在尝试编写一个单元测试用例来测试该方法，但我遇到了问题。

这是示例代码：

myService1

@Service
public class MyService1 {
    @Autowired
    private ServiceProperties serviceProperties;
    public void getMyLanguage(){
        String language =  serviceProperties.getLocale().getLanguage();
        printSomething(language);
    }
    private void printSomething(String input){
        System.out.print("your current language is " + input);
    }
}

ServiceProperties

import org.springframework.boot.context.properties.ConfigurationProperties;
import java.util.Locale;
@ConfigurationProperties(prefix = "conversation")
public class ServiceProperties {
    private ServiceProperties(){};
    private Locale locale;
    public Locale getLocale(){
        return locale;
    }
}

application.properties

conversation.locale=en_US

这是我的测试案例：

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.junit.MockitoJUnitRunner;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
@RunWith(MockitoJUnitRunner.class)
public class MyService1Test {
    @Mock
    private ServiceProperties serviceProperties;
    @InjectMocks
    private MyService1 myService1;
    @Test
    public void getMyLanguage(){
        when(serviceProperties.getLocale().getLanguage()).thenReturn("EN");
        myService1.getMyLanguage();
        verify(myService1).getMyLanguage();
    }
}

测试将触发NullPoInterException，因为我不想启动服务器（使用@springboottest注释）来加载上下文，因为该语言环境的属性未加载在测试中，是否有任何方法可以解决此问题，谁能帮忙？

Answer 1

问题在此行：

when(serviceProperties.getLocale().getLanguage()).thenReturn("EN");

因为serviceProperties被模拟，因此serviceProperties.getLocale()等于null。因此，当调用serviceProperties.getLocale().getLanguage()时，您会得到NullPointerException。

一个解决方法如下：

@RunWith(MockitoJUnitRunner.class)
public class MyService1Test {
    @Mock
    private ServiceProperties serviceProperties;
    @InjectMocks
    private MyService1 myService1;
    @Test
    public void getMyLanguage(){
        when(serviceProperties.getLocale()).thenReturn(new Locale("EN"));
        myService1.getMyLanguage();
        verify(myService1).getMyLanguage();
    }
}

Answer 2

现场注射对于测试不方便。您可以使用构造函数注入

@Service
public class MyService {

    private final ServiceProperties serviceProperties;
    @Autowired
    public MyService(ServiceProperties serviceProperties) {
        this.serviceProperties = serviceProperties;
    }
    //...
}

然后您将能够在每个测试之前注入模拟

@RunWith(MockitoJUnitRunner.class)
public class MyService1Test {
    @Mock
    private ServiceProperties serviceProperties;
    private MyService1 myService1;
    @Before
    public void createService(){
        myService1 = new MyService1(serviceProperties);
    }
}