Ignored Beans in SpringBootTest Configuration

Question

I have the following structure;

Main Config Class;

@TestConfiguration
@Import({MainApplication.class, ConfigA.class, ConfigB.class})
public class MainTestConfiguration {
}

And two separate config classes;

@TestConfiguration
public class ConfigA {
    @Bean
    public EtcDao etcDao() {
         // return custom etcDao
    }
}

@TestConfiguration
public class ConfigB {
    @Bean
    public SomeBean someBean() {
         // return custom someBean
    }
}

And the test is as following;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = MainTestConfiguration.class)
public class MotherTest {

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

With this structure, my test definitions of the beans EtcDao and SomeBean are ignored, and the main context definitions of these beans are used (from MainApplication.class). But if I include these separate configurations in @SpringBootTest like @SpringBootTest(classes = {ConfigA.class, ConfigB.class}), then it works properly. Doesn't @Include allow the beans in these individual configuration classes to be initialized? Or the culprit is my inclusion of MainApplication.class together with them, but I need other configuration from it so I had to implement in this manner.