Pitest report : not existing coverage on kotlin suspend method when it is spring component

[stanKluk]

Summary

Pitest does not seem to consider main kotlin suspend methods when they are part of a spring component module.
My project uses :

• kotlin
• spring webflux for reactive methods
• suspend methods
• junit 5
• pitest + pitest junit5 bridge

I have tried to use arcmutate plugins but the result is the same.
I have tried also to replace spring webflux by spring web.

Instructions to reproduce the problem

You can checkout this project to reproduce it : https://github.com/stanKluk/pitest-kotlin-spring-reactive-sample

Gradle configuration :

Plugins part :

plugins {
    id 'org.springframework.boot' version '2.7.18'
    id 'org.jetbrains.kotlin.jvm' version '2.0.20'
    id 'org.jetbrains.kotlin.plugin.spring' version '2.0.20'
    id 'info.solidsoft.pitest' version '1.15.0'
}

apply plugin: 'io.spring.dependency-management'
apply plugin: "info.solidsoft.pitest"

Dependencies :

dependencies {
    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.6.4'
    implementation 'org.springframework.boot:spring-boot-starter-webflux:2.7.18'
    //same result with implementation 'org.springframework.boot:spring-boot-starter-web:2.7.18'

    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.2'
    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.2'
}

Pitest plugin configuration :

pitest {
    pitestVersion = '1.18.2'
    //adds dependency to org.pitest:pitest-junit5-plugin and sets "testPlugin" to "junit5"
    junit5PluginVersion = '1.0.0'
    useClasspathFile = true
    timestampedReports = true
    detectInlinedCode = true
    targetClasses = ['com.fsk.*']
}

Class sample and its test :

@Component
class SuspendClassComponent {

    suspend fun callSomethingUseful(): Int {
        var result = 0
        val time = measureTimeMillis {
            val one = doSomethingUsefulOne()
            val two = doSomethingUsefulTwo()
            result = one + two
        }
        println("Completed in $time ms")
        return result
    }

    private suspend fun doSomethingUsefulOne(): Int {
        delay(1000L) // pretend we are doing something useful here
        return 13
    }

    private suspend fun doSomethingUsefulTwo(): Int {
        delay(1000L) // pretend we are doing something useful here, too
        return 29
    }
}

class SuspendClassTest {
    @Test
    fun `test something useful 2`() = runBlocking {
        val suspendClass = SuspendClassComponent()
        val result = suspendClass.callSomethingUseful()
        assertEquals(result, 42)
    }
}

Coverage result

As you can see below, the main suspend method is not shown in coverage report

Expected result

Without the @component annotation, everything works fine

And if I use @component annotation, without suspended methods, coverage is ok too

Am I doing something wrong ? I'm used to use pitest for Java/Maven but after a long research I can't find what could be incorrect.
Thank you
Stan

[hcoles]

Thanks for the report and the project to reproduce.

The compiler looks to be moving the code on lines 13 and 14 into a synthetic method, which is therefore not mutated. This is the sort of thing that the kotlin plugin should unravel, but it looks to be confused by the combination of the annotation and the suspend.

It will take a little time to work out what is going on, but hopefully the kotlin plugin's suspend support can be tweaked to fix this.