How does kotlintest test spring boot application

Question

The integration test of Spring boot application always starts the web server firstly.

The simplest test of spring boot test looks like below, how does migrate it using kotlintest instead?

@ExtendWith(SpringExtension::class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class ReportApplicationTests {

    @Test
    fun `Server can be launched`() {
    }

}

Answer 1

Here's how I've got it set up: firstly, make sure to reference JUnit 5 instead of 4, e.g. I've got this in the dependencies section of my build.gradle:

testImplementation "org.springframework.boot:spring-boot-starter-test:${springBootVersion}"
testImplementation "org.jetbrains.kotlin:kotlin-test"
testImplementation "org.jetbrains.kotlin:kotlin-test-junit"
testImplementation "io.kotlintest:kotlintest-extensions-spring:3.1.10"
testImplementation 'io.kotlintest:kotlintest-runner-junit5:3.1.10'
testImplementation "org.junit.jupiter:junit-jupiter-api:5.3.1"
testImplementation "org.junit.jupiter:junit-jupiter-engine:5.3.1"

Also add this to build.gradle:

test {
    useJUnitPlatform()
}

Then in your integration test class have this (notice the override of listeners, without which it won't work):

import org.springframework.boot.test.context.SpringBootTest
import io.kotlintest.spring.SpringListener

@SpringBootTest(
        webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT,
        classes = [MyApplication::class])
class MyTestStringSpec : StringSpec() {
    override fun listeners() = listOf(SpringListener)

    init {
        // Tests go in here
    }
}

Obviously you can replace StringSpec with any of the other Kotlin Test testing styles, e.g. FunSpec, ShouldSpec, etc.