春季测试类是否解决了它的自动关联

Question

I have a this class

@Component("A")
public class A {
    private B b;

    @Autowired
    public A(B b) {
        this.b = b;
    }
}

and another class

@Component("B")
public class B {

    public B() {

    }
}

Now I've written this test

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(loader=AnnotationConfigContextLoader.class)
public class ConstructorAutowiredTest {

    @Configuration
    static class ContextConfiguration {
        @Bean
        public B getBBean() {
            B b = new B();
            return b;
        }
    }

    @Autowired
    private B b;


    @Test
    public void isDependencyResolved() {
        assertNotNull(b);
    }
}

It works as well. But is there any way to test whether this B bean was automatically injected in A . I'm trying to so something like this but obviously it's not working.

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(loader=AnnotationConfigContextLoader.class)
public class ConstructorAutowiredTest {

    @Configuration
    static class ContextConfiguration {
        @Bean
        public B getBBean() {
            B b = new B();
            return b;
        }
    }

    @Autowired
    private A a;

    @Autowired
    private B b;


    @Test
    public void isDependencyResolved() {
        assertNotNull(b);
        assertNotNull(a);
    }
}

Exception:

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'com.abc.ConstructorAutowiredTest': 
Unsatisfied dependency expressed through field 'a'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: 
No qualifying bean of type 'com.abc.A' available: expected at least 1 bean which qualifies as autowire candidate. 
Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

Answer 1

You could have added to your configuration a component scan which uploads your @Component("A")

like this:

@Configuration
@ComponentScan("some.package")
static class ContextConfiguration {
    @Bean
    public B getBBean() {
        B b = new B();
        return b;
    }
}

This would resolve your exception, and then you could assert your Bean A if it has B inserted.

Answer 2

As far as I understand your question, I think you are using JUnit to test something that is not a unit test but something closer to an integration test, which is out of the scope of JUnit.

JUnit will always assume that you have initialized properly the class to be tested, dependency resolutions aren't its responsability.

And, as you have seen, Spring won't event let that test start if the dependencies are not solved