how to use @DynamicPropertySource to set webclient url in application properties in a kotlin spring boot integration test?

Question

I'm referencing this question posted here but trying to do the same thing in a kotlin spring boot integration test. I've modified the code to kotlin syntax like so

@DynamicPropertySource
fun properties(registry: DynamicPropertyRegistry) {
    registry.add("testApi.baseUrl", {"http://localhost:" + mockWebServer.port})
}

When I run my test, I'm getting an illegalStateException that

@DynamicPropertySource method 'properties' must be static

Trying to add the @JvmStatic annotation creates further problems as well. Is it possible to override a property this way in kotlin? I'd like to point all my webclients in my client classes to my mockwebserver for my integration test.

Answer 1

The Kotlin way of doing this is to use a companion object (caveat: I have not actually tried this)

companion object PropertiesSource {

  @DynamicPropertySource
  fun properties(registry: DynamicPropertyRegistry) {
    registry.add("testApi.baseUrl", 
      {"http://localhost:" + mockWebServer.port})
  }
}

UPDATE

Here is a working example that sets up the MockWebServer in a Kotlin SpringBootTest

package com.example.gradlebitch

import mu.KotlinLogging
import okhttp3.mockwebserver.MockWebServer
import org.junit.jupiter.api.AfterAll
import org.junit.jupiter.api.BeforeAll
import org.junit.jupiter.api.Test
import org.springframework.boot.test.context.SpringBootTest
import org.springframework.test.context.DynamicPropertyRegistry
import org.springframework.test.context.DynamicPropertySource
import reactor.core.publisher.Mono
import java.io.IOException
import java.time.temporal.ChronoUnit
import java.util.*

@SpringBootTest
class KotlinMockWebServerTest {
    companion object MockWebServerSetup {
        private val log = KotlinLogging.logger {}
        private val tenSec: java.time.Duration = java.time.Duration.of(10, ChronoUnit.SECONDS)
        private var untouchableMockWebServer: MockWebServer? = null // go through the mono, please
        private var webServerMono: Mono<MockWebServer> = Mono.fromCallable {
            Optional.ofNullable<MockWebServer>(untouchableMockWebServer)
                .orElseGet {
                    try {
                        log.warn("Starting Up Midpoint MockServer")
                        untouchableMockWebServer = MockWebServer()
                        untouchableMockWebServer!!.start()
                        log.warn(
                            "Midpoint MockServer running at: "
                                    + untouchableMockWebServer!!.url("")
                        )
                        return@orElseGet untouchableMockWebServer
                    } catch (e: IOException) {
                        throw RuntimeException(e)
                    }
                }

        }
        @JvmStatic
        @DynamicPropertySource
        fun testProperties(registry: DynamicPropertyRegistry) {
            log.warn("Setting provision.midpoint.uri to be dynamic")
            registry.add("provision.midpoint.uri") { mockUrl }
        }

        private val mockUrl: String
            get() = webServerMono.block(tenSec)?.url("").toString()

        @JvmStatic
        @BeforeAll
        @Throws(IOException::class)
        fun setUp() {
            log.warn("Waiting for MockWebServer")
            webServerMono.block(tenSec)
        }

        @JvmStatic
        @AfterAll
        @Throws(IOException::class)
        fun shutDownMockWebServer() {
            log.warn("Shutting Down MockWebServer at $mockUrl")
            webServerMono.block(tenSec)?.shutdown()
            untouchableMockWebServer = null
        }
    }

    @Test
    public fun testSomething() {
        log.warn("Mock Url: $mockUrl")
    }
}