[KotlinTest] Port remainging tests to Kotlin (#65)

* [KotlinTest] Port remainging tests to Kotlin

Closes #58

* formatting

* detekt

Author: Nava2

build.gradle.kts

@@ -72,23 +72,14 @@ dependencies {
   implementation("com.google.guava:guava:31.1-jre")
   implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:1.8.10")
 
-  testApi("junit:junit:4.13.2")
-
   testCompileOnly("org.jetbrains:annotations:24.0.1")
 
   testImplementation(localGroovy())
   testImplementation(gradleTestKit())
+  testImplementation("junit:junit:4.13.2")
   testImplementation("org.assertj:assertj-core:3.24.2")
 }
 
-tasks.compileTestGroovy {
-  classpath += files(tasks.compileTestKotlin.flatMap { it.destinationDirectory })
-}
-
-tasks.testClasses {
-  dependsOn(tasks.compileTestGroovy)
-}
-
 tasks.check {
   dependsOn(tasks.named("projectHealth"))
 }

src/test/groovy/org/assertj/generator/gradle/parameter/OutputDirectoryParameter.groovy

@@ -4,8 +4,8 @@ import org.assertj.core.api.AbstractObjectAssert
 import org.gradle.testkit.runner.BuildTask
 import org.gradle.testkit.runner.TaskOutcome
 
-fun <SELF : AbstractObjectAssert<SELF, BuildTask?>> SELF.isSuccessful(): SELF = isOutcome(TaskOutcome.SUCCESS)
-fun <SELF : AbstractObjectAssert<SELF, BuildTask?>> SELF.isUpToDate(): SELF = isOutcome(TaskOutcome.UP_TO_DATE)
+internal fun <SELF : AbstractObjectAssert<SELF, BuildTask?>> SELF.isSuccessful(): SELF = isOutcome(TaskOutcome.SUCCESS)
+internal fun <SELF : AbstractObjectAssert<SELF, BuildTask?>> SELF.isUpToDate(): SELF = isOutcome(TaskOutcome.UP_TO_DATE)
 
 private fun <SELF : AbstractObjectAssert<SELF, BuildTask?>> SELF.isOutcome(outcome: TaskOutcome): SELF {
   extracting { it?.outcome }.`as` { "task.outcome == $outcome" }.isEqualTo(outcome)

src/test/groovy/org/assertj/generator/gradle/parameter/SkipParameter.groovy

@@ -5,11 +5,11 @@ import java.io.File
 import java.nio.file.Path
 import kotlin.io.path.writeText
 
-fun File.writeJava(@Language("java") content: String): Unit = writeText(content.trimIndent())
-fun Path.writeJava(@Language("java") content: String): Unit = writeText(content.trimIndent())
+internal fun File.writeJava(@Language("java") content: String): Unit = writeText(content.trimIndent())
+internal fun Path.writeJava(@Language("java") content: String): Unit = writeText(content.trimIndent())
 
-fun File.writeGroovy(@Language("groovy") content: String): Unit = writeText(content.trimIndent())
-fun Path.writeGroovy(@Language("groovy") content: String): Unit = writeText(content.trimIndent())
+internal fun File.writeGroovy(@Language("groovy") content: String): Unit = writeText(content.trimIndent())
+internal fun Path.writeGroovy(@Language("groovy") content: String): Unit = writeText(content.trimIndent())
 
-fun File.writeKotlin(@Language("kotlin") content: String): Unit = writeText(content.trimIndent())
-fun Path.writeKotlin(@Language("kotlin") content: String): Unit = writeText(content.trimIndent())
+internal fun File.writeKotlin(@Language("kotlin") content: String): Unit = writeText(content.trimIndent())
+internal fun Path.writeKotlin(@Language("kotlin") content: String): Unit = writeText(content.trimIndent())

src/test/kotlin/org/assertj/generator/gradle/AssertExtensions.kt

@@ -12,17 +12,13 @@
  */
 package org.assertj.generator.gradle
 
-import groovy.lang.GString
 import org.intellij.lang.annotations.Language
 import java.io.File
 
 /**
  * Utilities used in test scripts
  */
 internal object TestUtils {
-  @JvmStatic
-  fun File.writeBuildFile(@Language("Groovy") content: GString) = writeBuildFile(content.toString())
-
   @JvmStatic
   fun File.writeBuildFile(@Language("Groovy") content: String) {
     writeGroovy(