Kotlin: Unable to directly invoke suspended service methods that require the Vertx context in unit tests

[aaronz-vipaso]

Describe the bug

I can't directly call suspended service class methods that access the DB (requires the Vert.x context)

See this reproducer

The test fails because of: io.vertx.core.VertxException: Thread blocked

However, it works fine when the service method is called implicitly by RestAssured over the resource class. Also, refer to the reproducer here.

Expected behavior

I can invoke service class methods that require a Vert.x context from unit tests.

Actual behavior

It hangs. Maybe related to #41288

How to Reproduce?

Reproducer: https://github.com/aaronz-vipaso/quarkus-kotlin-dispatcher

1. ./gradlew test --tests NameServiceTest – does not work
2. ./gradlew test --tests NameResourceTest – does work

Output of uname -a or ver

Darwin Aarons-MacBook-Pro.local 24.1.0 Darwin Kernel Version 24.1.0: Thu Oct 10 21:03:11 PDT 2024; root:xnu-11215.41.3~2/RELEASE_ARM64_T6020 arm64

Output of java -version

openjdk version "17.0.6" 2023-01-17 LTS OpenJDK Runtime Environment Corretto-17.0.6.10.1 (build 17.0.6+10-LTS) OpenJDK 64-Bit Server VM Corretto-17.0.6.10.1 (build 17.0.6+10-LTS, mixed mode, sharing)

Quarkus version or git rev

3.18.3

Build tool (ie. output of mvnw --version or gradlew --version)

------------------------------------------------------------ Gradle 8.12 ------------------------------------------------------------ Build time: 2024-12-20 15:46:53 UTC Revision: a3cacb207fec727859be9354c1937da2e59004c1 Kotlin: 2.0.21 Groovy: 3.0.22 Ant: Apache Ant(TM) version 1.10.15 compiled on August 25 2024 Launcher JVM: 17.0.6 (Amazon.com Inc. 17.0.6+10-LTS) Daemon JVM: /Users/name/.sdkman/candidates/java/17.0.6-amzn (no JDK specified, using current Java home) OS: Mac OS X 15.1.1 aarch64

Additional information

No response

[quarkus-bot]

/cc @geoand (kotlin)

[aaronz-vipaso]

@geoand Well, I managed to "fix" it.

It works when I set runOnEventLoop = false in the @RunOnVertxContext annotation:

@Test
@RunOnVertxContext(runOnEventLoop = false)
fun `should create a name`() = runTest {
    val vertxDispatcher = Vertx.currentContext()!!.dispatcher()

    withContext(vertxDispatcher) {
        val response = nameService.create("Aaron")
        assertEquals("Aaron", response.name)
    }
}

However, I'm unsure why it works, and it would be nice to have a more elegant native solution for this Kotlin scenario.

---

For now, I have created this helper function to make repetitive usage easier:

fun <T> runVertxTest(block: suspend () -> T) {
    runTest {
        val vertxContext: Context = Vertx.currentContext()
            ?: throw IllegalStateException("Unit test must be annotated with @RunOnVertxContext(runOnEventLoop = false)")

        withContext(vertxContext.dispatcher()) {
            block()
        }
    }
}

@Test
@RunOnVertxContext(runOnEventLoop = false)
fun `should create a name`() = runVertxTest {
    val response = nameService.create("Aaron")
    assertEquals("Aaron", response.name)
}

[geoand]

We have done no testing and no integration work with kotlinx.coroutines.test.runTest, so I don't hae any answers for you