`@MockitoBean` with custom `@Qualifier` is not injected into `@Configuration` class

[duoduobingbing]

Problem

When a @MockitoBean is annotated with a custom @Qualifier it cannot be injected into a @Configuration class when there is a normal bean with said qualifier.

Reproducer

Reproducer Test

@ExtendWith(SpringExtension.class)
public class QualifierAnnotationTest {

    @MockitoBean
    @MyQualifier
    private IExample myExample;

    @Autowired
    private MyExampleCaller caller;

    @Test
    public void test() {

    }

    public interface IExample {

        String value();

    }

    public static class MyExampleCaller  {

        IExample example;

        public MyExampleCaller(IExample example) {
            this.example = example;
        }

    }

    @Qualifier
    @Retention(RetentionPolicy.RUNTIME)
    public @interface MyQualifier {

    }

    @MyQualifier
    public static class QualifierExample implements IExample {

        @Override
        public String value() {
            return "QualifierExample";
        }

    }

    @Configuration(proxyBeanMethods = false)
    static class TestConfig {

        @Bean
        public QualifierExample toBeReplacedByMock() {
            return new QualifierExample();
        }

        @Bean
        MyExampleCaller controller(@MyQualifier IExample example) {
            return new MyExampleCaller(example);
        }

    }
}

The test fails with:

org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.example.qualifiermockitobeanbug.QualifierAnnotationTest$IExample' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.example.qualifiermockitobeanbug.QualifierAnnotationTest.MyQualifier()}

Workaround

Replacing @MockitoBean with @MockBean causes the test to succeed.

[sbrannen]

Hi @duoduobingbing,

Congratulations on submitting your first issue for the Spring Framework! 👍

And thanks for the well-crafted reproducer.

This turns out to be an interesting case. We have support for @Qualifier and various tests which verify that support; however, we did not have a test which exercises the scenario you have presented.

The core of the issue is that your toBeReplacedByMock() method declares QualifierExample as the return type (which is in fact annotated with @MyQualifier. However, you explicitly instructed Spring to create a mock based on the IExample interface via the @MockitoBean myExample field in the test class. Thus, the IExample mock effectively replaces what would otherwise have been a QualifierExample in the ApplicationContext.

In other words, in your example there is no longer a bean of type IExample in the context which is also annotated with @MyQualifier. Hence, the exception you encountered.

To work around this with @MockitoBean, you have a few options.

1. Either annotate the toBeReplacedByMock() method with @MyQualifier.
2. Or change the type of the myExample field to QualifierExample and remove the @MyQualifier declaration on the field.
3. Or change the return type of the toBeReplacedByMock() method to IExample and annotate the method with @MyQualifier.

The latter two options are preferable, since they do not result in different types of beans being present in the final state of the ApplicationContext; whereas, option 1 (as well as your unmodified example when using Spring Boot's @MockBean) results in no bean of type QualifierExample in the ApplicationContext (as mentioned above), which could lead to bugs depending on what other components expect to be available in the context.

Although there are workarounds, we do consider this a bug since it worked in Spring Boot. Furthermore, we aim to have consistent support for custom @Qualifier annotations with the Bean Override support in Spring Framework as well. Consequently, I have been working on a fix for this that I will soon commit.

Regards,

Sam

[sbrannen]

This has been fixed in 374c3b4 for inclusion in the upcoming 6.2.6 release.

If you would like to try it out before then, feel free to test against 6.2.6 snapshots.