Support expressing application args in @SpringBootTest

[jgriff]

Add args property to the @SpringBootTest annotation so tests
can easily supply application arguments to pass to their app under test.

For example,

@SpringBootTest(args = {"--some.option=some-value", "other.arg=other-value"})
public class SpringBootTestArgsTest {
	@Autowired
	private ApplicationArguments args;

	@Test
	public void applicationArgumentsPopulated() {
		assertThat(args.getOptionNames()).contains("some.option");
		assertThat(args.getNonOptionArgs()).contains("other.arg=other-value");
	}
}

[wilkinsona]

Thanks for the PR. I think there’s a risk that this will give a false sense of security if a mistake has been made in the application’s main method and the args aren’t passed to SpringApplication. That said, I can see the benefit in terms of ApplicationArguments.

My feeling at the moment is that it may be better to unit test anything that uses ApplicationArguments. Let’s see what the rest of the team thinks.

[snicoll]

My feeling at the moment is that it may be better to unit test anything that uses ApplicationArguments.

+1

[jgriff]

Yes, I see what you mean on the potential to overlook the responsibility of the app's main() method to forward the args to SpringApplication. Also agree on the strategy to unit test consumers of ApplicationArguments in isolation.

The primary motivation for this is to support integration tests driven by @SpringBootTest. In particular, those with anonymous ApplicationRunner beans.

@Bean
public ApplicationRunner doOnStartup() {
        return args -> ... 
    }
}

[wilkinsona]

We've discussed this today and we think you've convinced us. Tentatively assigning to 2.x.

[jgriff]

:)

[snicoll]

@jgriff thank you for making your first contribution to Spring Boot. This is now merged in master with a polish commit.