java - How to test main class of Spring-boot application

Question

I have a spring-boot application where my @SpringBootApplication starter class looks like a standard one. So I created many tests for all my functionalities and send the summary to sonarqube to see my coverage.

For my starter class Sonarqube tells me that I just have 60% coverage. So the average coverage is not good as expected.

My Test class is just the default one.

@RunWith(SpringRunner.class)
@SpringBootTest(classes = ElectronicGiftcardServiceApplication.class)
public class ElectronicGiftcardServiceApplicationTests {

    @Test
    public void contextLoads() {
    }
}

So how can I test my main class in the starter class of my application?

Answer 1

All these answers seem overkill.
You don't add tests to make a metric tool happy.
Loading a Spring context of the application takes time. Don't add it in each developer build just to win about 0.1% of coverage in your application.
Here you don't cover only 1 statement from 1 public method. It represents nothing in terms of coverage in an application where thousands of statements are generally written.

First workaround : make your Spring Boot application class with no bean declared inside. If you have them, move them in a configuration class (for make them still cover by unit test). And then ignore your Spring Boot application class in the test coverage configuration.

Second workaround : if you really need to to cover the main() invocation (for organizational reasons for example), create a test for it but an integration test (executed by an continuous integration tool and not in each developer build) and document clearly the test class purpose :

import org.junit.Test;

// Test class added ONLY to cover main() invocation not covered by application tests.
public class MyApplicationIT {
   @Test
   public void main() {
      MyApplication.main(new String[] {});
   }
}