How to add coverage report (JaCoCo) to kotest based using build.gradle.kts? - kotlin

Question

I use Kotlin for server side, and I want to add test coverage (by using JaCoCo but can be any other open source).
At the moment, I don't find any documentation to explain how to enable/add coverage report to kotlin project based on kotest which actually works.
(Yes I tried the official documentation)
build.gradle.kts:
import Libraries.coroutines
import Libraries.koTest
import Libraries.koTestCore
import Libraries.mockk
import Libraries.testcontainers
import Libraries.testcontainersPostgres
plugins {
java
`kotlin-dsl` version "1.3.5" apply false
kotlin("jvm") version Versions.kotlin_version
kotlin("plugin.serialization") version Versions.kotlin_version apply false
id("com.diffplug.gradle.spotless") version Plugins.spotless
id("com.palantir.docker") version Plugins.docker apply false
id("com.palantir.docker-run") version Plugins.docker apply false
id("com.google.protobuf") version Plugins.protobuf apply false
id("org.flywaydb.flyway") version Plugins.flyway apply false
}
allprojects {
group = "my-app"
version = "2.0"
apply(plugin = "kotlin")
apply(plugin = "com.diffplug.gradle.spotless")
repositories {
mavenCentral()
jcenter()
}
tasks {
compileKotlin {
dependsOn(spotlessApply)
kotlinOptions {
jvmTarget = "11"
}
}
compileTestKotlin {
kotlinOptions {
jvmTarget = "11"
}
}
}
java {
sourceCompatibility = JavaVersion.VERSION_11
targetCompatibility = JavaVersion.VERSION_11
}
tasks.withType<Test> {
useJUnitPlatform()
maxParallelForks = 1
environment("ENV", "test")
}
afterEvaluate {
project.configurations.forEach {
// Workaround the Gradle bug resolving multiplatform dependencies.
if (it.name.contains("Proto")) {
it.attributes.attribute(Usage.USAGE_ATTRIBUTE, objects.named(Usage::class.java, Usage.JAVA_RUNTIME))
}
}
}
}
subprojects {
spotless {
kotlin {
ktlint().userData(mapOf("disabled_rules" to "no-wildcard-imports"))
trimTrailingWhitespace()
endWithNewline()
}
}
dependencies {
implementation(coroutines)
testImplementation(koTest)
testImplementation(koTestCore)
testImplementation(mockk)
testImplementation(testcontainers)
testImplementation(testcontainersPostgres)
}
configurations {
all {
resolutionStrategy.setForcedModules("org.apache.httpcomponents:httpclient:4.5.9")
}
}
}
Any help will be great. Thanks in advance.

Answer 1

in my experience, Jacoco and Kotest interoperate just fine out of the box. I'm using it and all I need to do is the following:
plugins {
jacoco
// The rest of your plugins
}
// Your build, as it was before
You can inspect a working Jacoco + Kotest build here.
To verify that it works, you can e.g., feed the Jacoco generated data to services such as Codecov.io.
First, generate the report in XML format:
tasks.jacocoTestReport {
reports {
xml.isEnabled = true
}
}
And then use the Codecov.io service to fetch and analyze the results:
bash <(curl -s https://codecov.io/bash)
As you can see in this report, Jacoco is doing its job without further configuration.