Spring Boot, test main application class

Question

I have a logic in my application class in a Spring Boot app, but I don't know how to do an unit and an integration test to cover it.

Here is the code.

    @SpringBootApplication
    public class MlgApplication {

        public static void main(String[] args) throws IOException {
            ConfigurableApplicationContext run = SpringApplication.run(MlgApplication.class, args);

            ListBean ListBean = run.getBean(ListBean.class);
            ListBean.createList();
        }
    }

It's a command line application that runs with 'java -jar mlg.jar'

score 1 · Answer 1 · answered Aug 14 '18 at 12:47

If you are using Spring initializr, this test will be created for you. You may call it an integration test because it will try to start your application context (thus integrating all classes inisde it). It goes something like this:

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

    @Test
    public void contextLoads() {
    // some more optional integration assertions here
    // like asserting number of beans, are they null, etc...
    }
}

And for your specific domain logic, you can try to assert if the list is created but I would put that in a separate class as a unit test.

score 0 · Answer 2 · answered Feb 26 '21 at 22:18

I managed to do it this way, using mockito-core 3.8 and mockito-inline BUT was not able to get Jacoco coverage doing it this way:

@SpringBootTest
@ActiveProfiles("test")
public class AutowireTest {

    private static final String ARG = "";
    private static final String[] ARGS = new String[]{ARG};

    @Autowired
    ConfigurableApplicationContext context;

    @Test  //Junit5
    public void main() {
        try (MockedStatic<Application> appStatic = Mockito.mockStatic(Application.class);
             MockedStatic<SpringApplication> springStatic = Mockito.mockStatic(
               SpringApplication.class)) {
            appStatic.when(() -> Application.main(ARGS))
                .thenCallRealMethod();
            springStatic.when(() -> SpringApplication.run(Application.class, ARGS))
                .thenReturn(context);

            // when
            Application.main(ARGS);

            //then
            appStatic.verify(times(1),
                () -> Application.main(ARGS));
            springStatic.verify(times(1),
                () -> SpringApplication.run(Application.class, ARGS));
        }
    }
}

So, I am asking why here: How to Unit test Spring-Boot Application main() method to get Jacoco test coverage

Spring Boot, test main application class

2 Answers2

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