Spring：在 Junit 中加载的类中自动装配不同的类

Question

I have the following scenario in Spring :

public class ClassA{

@Autowired
private ClassB classB;
}

I'm using (Autowiring to be more precise) ClassA in my Test class. But what I'd like to do somehow is to modify ClassB just for my Junit, so with that, When ClassA is autowired in my test class, it loads the modified ClassB (instead of the original one).

Is there a way to achive that?

Answer 1

Can't think of another way to do this without Bean Configuration. You can configure this in 2 ways:

First:

@Configuration
public class AppConfig {

  @Bean
  public ClassB classB() {
    return new ClassB() {
      // this is a subclass that inherits everything from ClassB, so override what you want here
    }
  }
}

Second: (taken from here )

@RunWith(SpringRunner.class)
@SpringBootTest
public class SomeTest {

  // do this if you only want the modified classB in 1 place
  @Configuration
  static class TestConfig {
      @Bean
      public ClassB classB () {
          return new ClassB() {
            // same as the first
          }
      }
  }

  @Test
  public void testMethod() {
    // test
  }
}

Finally, you could create a new interface ClassB and ClassBImpl in your main folder and ClassBTestImpl in your test folder. You still need to use one of the configuration.