How to write a test for the Application class in Spring Boot for Kotlin

Question

import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication

@SpringBootApplication
class GetThingsDoneApplication

fun main(args: Array<String>) {
    runApplication<GetThingsDoneApplication>(*args)
}

I am trying to push my test coverage for my project to 100%. But I don't know how to write a test for main(args: Array<String>)

I guess the Test Class and method should look something like this:

import org.assertj.core.api.Assertions.assertThat
import org.junit.jupiter.api.Test

@ContextConfiguration(classes = [GetThingsDoneApplication::class])
class GetThingsDoneApplicationIntegrationTest {

    @Test
    fun contextLoads() {
        main(doSomething())
    }

    private fun doSomething(): Array<String> {
        return arrayOf<String>()
    }
}

The question is now, how should my assertThat look like, to have 100% test coverage?

Answer 1

This works for me

import org.junit.jupiter.api.Test
import org.springframework.boot.test.context.SpringBootTest
import org.springframework.test.context.ActiveProfiles
import kotlin.test.assertTrue

@SpringBootTest
@ActiveProfiles("test")
internal class SomeAppTest {

    @Test
    fun contextloads() {
        assertTrue { true }
    }
}

When you say Failed to load ApplicationContext can you provide the whole stack trace, please?

Answer 2

Actually the most effective way to get 100% is to exclude the Application.kt file from the test coverage, like described here IntelliJ - exclude some classes (packages) from test coverage report