Question

我正在尝试编写一个单元测试用例来测试该方法，但是遇到问题。

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);
    }
}

服务属性

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

这是我的测试用例：

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();
    }
}

该测试将触发nullpointerexception，因为在测试中未加载语言环境的属性，如果我不想启动服务器（使用@SpringBootTest批注）来加载上下文，是否有任何方法可以解决此问题，有人可以帮忙吗？

Answer 1

问题出在这一行：

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

由于serviceProperties被嘲笑，因此serviceProperties.getLocale()等于null。因此，在调用NullPointerException时得到serviceProperties.getLocale().getLanguage()。

一种解决方法如下：

@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

现场注入不便于测试。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;
    }
    //...
}

然后您将能够在每次测试之前注入模拟

@RunWith(MockitoJUnitRunner.class)
public class MyService1Test {
    @Mock
    private ServiceProperties serviceProperties;

    private MyService1 myService1;

    @Before
    public void createService(){
        myService1 = new MyService1(serviceProperties);
    }
}

如何在Mockito测试中从application.properties加载属性

2 个答案: