[英]Mockito and Javax annotation @PostConstruct
I'm writing a Java unit test using JUnit Jupiter for a class which has a method with a javax.annotation.PostConstruct
annotation.我正在使用 JUnit Jupiter 为一个类编写 Java 单元测试,该类具有带有
javax.annotation.PostConstruct
注释的方法。
I want to test a method in the class but am hitting an issue where the @PostConstruct
method is always called once the object is created (unsurprisingly).我想测试类中的一个方法,但遇到了一个问题,即一旦创建对象,@
@PostConstruct
方法总是被调用(不出所料)。 The Mockito mock object I've created to be used in the @PostConstruct
method isn't providing the results I require.我创建的用于
@PostConstruct
方法的 Mockito 模拟对象没有提供我需要的结果。
Here's the method that is being called when the object is created:这是创建对象时调用的方法:
@Service
@Slf4j
public class MyService {
@Inject
private MyRepository myRepository;
private Integer myId;
@PostConstruct
public void postInit() {
MyObject myObj = myRepository.findByName("FOO");
myId = myObj.getId();
}
public void myMethod() {
... code to be tested here...
}
}
My JUnit test class contains the following:我的 JUnit 测试类包含以下内容:
@ExtendWith(SpringExtension.class)
@DirtiesContext(classMode = DirtiesContext.ClassMode.AFTER_EACH_TEST_METHOD)
public class MyServiceTest {
private static final Integer ID = 0;
@Test
public void myTest() {
// Given.
MyObject myObj = new MyObject();
myObj.setId(ID);
MyRepository myRepository = Mockito.mock(MyRepository.class);
Mockito.when(myRepository.findByName(anyString())).thenReturn(myObj);
// Test runs here.
myService.myMethod()
}
}
When I run the unit test, I can see that the mock has been instantiated via my IDE.当我运行单元测试时,我可以看到模拟已通过我的 IDE 实例化。 However, it always returns a NULL object when the
findByName("FOO")
method is called, even though it should return a correct instance of MyObject
.然而,当调用
findByName("FOO")
方法时,它总是返回一个 NULL 对象,即使它应该返回一个正确的MyObject
实例。
As such, the unit test fails with a NullPointerException because myObj
is null.因此,单元测试失败并返回 NullPointerException,因为
myObj
为 null。
Is there anything obviously incorrect that I'm doing here>?我在这里做的有什么明显不正确的>?
Thanks in advance for any assistance.在此先感谢您的帮助。
I've modified your test slightly, creating MyService
via Mockito
and making myMethod
return the id:我稍微修改了您的测试,通过
Mockito
创建MyService
并使myMethod
返回 id:
@ExtendWith(SpringExtension.class)
class MyServiceTest {
private static final Integer ID = 42;
@InjectMocks
MyService myService;
@Test
public void myTest() {
// Given.
MyObject myObj = new MyObject();
myObj.setId(ID);
MyRepository myRepository = Mockito.mock(MyRepository.class);
Mockito.when(myRepository.findByName(anyString())).thenReturn(myObj);
// Test runs here.
assertThat(myService.myMethod()).isEqualTo(ID);
}
}
When I run this, I get:当我运行这个时,我得到:
java.lang.NullPointerException: Cannot invoke "java.lang.Integer.intValue()" because "this.myId" is null
at MyService.myMethod(MyService.java:24)
at MyServiceTest.myTest(MyServiceTest.java:28)
...
So clearly our mocking of findByName
hasn't worked.很明显,我们对
findByName
的嘲笑没有奏效。
That's because myRepository
is just a local variable in our test -- there's nothing to get it injected into MyService
.那是因为
myRepository
在我们的测试中只是一个局部变量——没有什么可以将它注入MyService
。
One way to fix this is not to use spring test infrastructure, just plain Mockito.解决此问题的一种方法是不使用 spring 测试基础架构,而只是使用普通的 Mockito。 We use the standard @Mock/@InjectMocks annotations to create our mock and the object we are testing.
我们使用标准的@Mock/@InjectMocks 注释来创建我们的模拟和我们正在测试的对象。 The drawback here is that we must remember to call
postInit
ourselves:这里的缺点是我们必须记住自己调用
postInit
:
@ExtendWith(MockitoExtension.class)
class MyServiceTest {
private static final Integer ID = 42;
@Mock
MyRepository myRepository;
@InjectMocks
MyService myService;
@Test
public void myTest() {
// Given.
MyObject myObj = new MyObject();
myObj.setId(ID);
Mockito.when(myRepository.findByName(anyString())).thenReturn(myObj);
myService.postInit();
// Test runs here.
assertThat(myService.myMethod()).isEqualTo(ID);
}
}
To use Spring to call postInit you can do this: (I'm not sure if there's a more idiomatic way to create the mock MyRepository instance)要使用 Spring 调用 postInit,您可以这样做:(我不确定是否有更惯用的方法来创建模拟 MyRepository 实例)
@ExtendWith(SpringExtension.class)
@SpringBootTest(classes = {MyService.class})
@ContextConfiguration(classes = {MyServiceTest.Configuration.class})
class MyServiceTest {
@TestConfiguration
static class Configuration {
@Bean
public MyRepository myRepository() {
MyRepository myRepository = mock(MyRepository.class);
MyObject myObj = new MyObject();
myObj.setId(ID);
Mockito.when(myRepository.findByName(anyString())).thenReturn(myObj);
return myRepository;
}
}
private static final Integer ID = 42;
@Autowired
MyService myService;
@Test
public void myTest() {
assertThat(myService.myMethod()).isEqualTo(ID);
}
}
One way to avoid using @SpringBootTest
is to create the MyService
instance in our test configuration (I've converted it to constructor injection too):避免使用
@SpringBootTest
一种方法是在我们的测试配置中创建MyService
实例(我也将其转换为构造函数注入):
@ExtendWith(SpringExtension.class)
@ContextConfiguration(classes = {MyServiceTest.Configuration.class})
class MyServiceTest {
@TestConfiguration
static class Configuration {
@Bean
public MyRepository myRepository() {
MyRepository myRepository = mock(MyRepository.class);
MyObject myObj = new MyObject();
myObj.setId(ID);
Mockito.when(myRepository.findByName(anyString())).thenReturn(myObj);
return myRepository;
}
@Bean
public MyService myService(MyRepository myRepository) {
return new MyService(myRepository);
}
}
private static final Integer ID = 42;
@Autowired
MyService myService;
@Test
public void myTest() {
assertThat(myService.myMethod()).isEqualTo(ID);
}
}
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