Gatling performance test with Scala and Gradle - scala

Question

I am new to Gatling and Scala , I am trying to run the Gatling test example specified in the beginning parts of this video: https://www.youtube.com/watch?v=To7LJiK87Us, but using Gradle wrapper.
I created a gradle project in IntelliJ idea and the build.gradle file is below
buildscript {
repositories {
maven {
url '<url>'
credentials {
<><>
}
}
}
dependencies {
classpath "gradle.plugin.io.gatling.gradle:gatling-gradle-plugin:3.8.4"
}
}
apply plugin: "io.gatling.gradle"
apply plugin: 'scala'
repositories {
maven {
url '<>'
credentials {
<><>
}
}
mavenCentral()
}
dependencies {
implementation 'org.scala-lang:scala-library:2.12.4'
gatling 'org.scala-lang:scala-library:2.12.4'
gatling 'au.com.bytecode:opencsv:2.4'
gatling group: 'org.scalaj', name: 'scalaj-http_2.12', version: '2.3.0'
gatling group: 'org.json4s', name: 'json4s-native_2.12', version: '3.5.3'
}
compileGatlingScala {
scalaCompileOptions.additionalParameters = ["-feature"]
}
gatling {
simulations = {
// Enable ALL perf testing, regardless of current pass/fail state
include "**/simulation/*Simulation*.scala"
}
}
sourceSets.gatling.resources.srcDir('conf')
gatling {
logLevel = 'WARN' // logback root level
logHttp = 'ALL'
}
Note: I have a few extra dependencies here like 'opencsv' that I will be needing later for the actual performance testing.
And my LoadSimulation script is as below
class LoadSimulation extends Simulation {
val scn = scenario("JSON")
.exec(
http("GET")
.get("http://jsonplaceholder.typicode.com/comments")
)
setUp(
scn.inject(atOnceUsers(1))
)
}
When I try to run the performance test using gradlew, it says "build successful', but I don't see a result in the reports folder under /build
>gradlew gatlingRun-LoadSimulation
BUILD SUCCESSFUL in 1s
3 actionable tasks: 1 executed, 2 up-to-date
Could anyone please tell me what I am doing wrong? Is this not how I should be running it?
EDIT
Updated to below dependencies as per answers below, still the same result, nothing in the /build/reports/gatling folder.
dependencies {
implementation 'org.scala-lang:scala-library:2.13'
gatling 'org.scala-lang:scala-library:2.13'
gatling 'au.com.bytecode:opencsv:2.4'
gatling group: 'org.scalaj', name: 'scalaj-http_2.13', version: '2.4.2'
gatling group: 'org.json4s', name: 'json4s-native_2.13', version: '3.6.7'
}

Answer 1

There's something very wrong: you're enforcing Scala 2.12 and Scala 2.12 based libraries while using Gatling 3.8 that requires Scala 2.13.
Please have a look at the official sample project: https://github.com/gatling/gatling-gradle-plugin-demo-scala/blob/main/build.gradle

Answer 2

In scala language the minor versions are actually major versions. You can expect a lot of differences between 2.12 and 2.13. Thats the problem you are facing.
Its like comparing Java 7 and Java 8.
I had the same confusion back in the days with the way Scala versions work.