How do I test private annotation aspect in spring boot?

Question

How do I test private annotation aspect in spring boot ?

Example:

@Aspect
@Component
@Slf4j
public class AspectClass {
    @AfterReturning(value = "@annotation(CustomAnnotation)")
    private void privateMethod(JoinPoint joinPoint) 
    {
       // Test this part
       System.out.println("Want to test this");
    }
}

@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.METHOD, ElementType.TYPE })
public @interface  CustomAnnotation {
    String methodName() default "";
}

Expect to test the private method in Aspect with annotation trigger

Answer 1

If your application is spring-boot-web then you can use your existing Application.java or you have to ceate a new ApplicationTest.java that atleast have the following

@Configuration
@SpringBootApplication
public class ApplicationTest {}

Sample Test:

// AnnotationExecutor.java
@Component
public class AnnotationExecutor {

    @CustomAnnotation(methodName = "CustomAnnotation")
    public void someMethod(...) {
       // code
       ...
    }

}

// AnnotationTest.java
@ExtendWith(SpringExtension.class)
@SpringBootTest(classes = ApplicationTest.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@ActiveProfiles("test")
@ComponentScan("com.your.package.path.*")
public class AnnotationTest {

    @Autowired
    private AnnotationExecutor annotationExecutor;

    @Test
    public void sampleTest(){
        annotationExecutor.someMethod(...);
        System.out.println("Test completed");
        // continue for assertion and testing ...
    }
}

Expected output:

Want to test this
Test completed
\\ ...