Add test for multiplatform plugin.

^KT-43095 In Progress

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/KotlinJavaToolchainTest.kt

@@ -12,7 +12,6 @@ import org.gradle.testkit.runner.BuildResult
 import org.gradle.util.GradleVersion
 import org.jetbrains.kotlin.gradle.testbase.*
 import org.junit.jupiter.api.DisplayName
-import org.junit.jupiter.api.Test
 import java.io.File
 
 @SimpleGradlePluginTests
@@ -118,7 +117,6 @@ class KotlinJavaToolchainTest : KGPBaseTest() {
             projectName = "simple".fullProjectName,
             gradleVersion = gradleVersion,
             projectPathAdditionalSuffix = "1/cache-test",
-            forceOutput = true,
             buildOptions = defaultBuildOptions.copy(buildCacheEnabled = true)
         ) {
             enableLocalBuildCache(buildCache)
@@ -135,7 +133,6 @@ class KotlinJavaToolchainTest : KGPBaseTest() {
             projectName = "simple".fullProjectName,
             gradleVersion = gradleVersion,
             projectPathAdditionalSuffix = "2/cache-test",
-            forceOutput = true,
             buildOptions = defaultBuildOptions.copy(buildCacheEnabled = true)
         ) {
             enableLocalBuildCache(buildCache)
@@ -303,8 +300,7 @@ class KotlinJavaToolchainTest : KGPBaseTest() {
     internal fun setJdkUsingJavaToolchain(gradleVersion: GradleVersion) {
         project(
             projectName = "simple".fullProjectName,
-            gradleVersion = gradleVersion,
+            gradleVersion = gradleVersion
-            forceOutput = true
         ) {
             useToolchainToCompile(11)
             build("assemble") {
@@ -319,8 +315,7 @@ class KotlinJavaToolchainTest : KGPBaseTest() {
     internal fun setJdkUsingJavaToolchainViaExtension(gradleVersion: GradleVersion) {
         project(
             projectName = "simple".fullProjectName,
-            gradleVersion = gradleVersion,
+            gradleVersion = gradleVersion
-            forceOutput = true
         ) {
             useToolchainExtension(11)
             build("assemble") {
@@ -329,6 +324,22 @@ class KotlinJavaToolchainTest : KGPBaseTest() {
         }
     }
 
+    @DisplayName("Toolchain should be correctly supported in multiplatform plugin jvm targets")
+    @GradleTestVersions(minVersion = "6.7.1")
+    @GradleTest
+    internal fun toolchainCorrectlySupportedInMPPlugin(gradleVersion: GradleVersion) {
+        project(
+            projectName = "mppJvmWithJava".fullProjectName,
+            gradleVersion = gradleVersion
+        ) {
+            useToolchainToCompile(11)
+
+            build("assemble") {
+                assertJdkHomeIsUsingJdk(getToolchainExecPathFromLogs())
+            }
+        }
+    }
+
     private fun BuildResult.assertJdkHomeIsUsingJdk(
         javaexecPath: String
     ) = assertOutputContains("[KOTLIN] Kotlin compilation 'jdkHome' argument: $javaexecPath")

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-java-toolchain/mppJvmWithJava/build.gradle

@@ -0,0 +1,14 @@
+plugins {
+    id "org.jetbrains.kotlin.multiplatform"
+}
+
+repositories {
+    mavenLocal()
+    mavenCentral()
+}
+
+kotlin {
+    jvm("jvmWithJava") {
+        withJava()
+    }
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-java-toolchain/mppJvmWithJava/settings.gradle

@@ -0,0 +1,10 @@
+pluginManagement {
+    repositories {
+        mavenLocal()
+        mavenCentral()
+    }
+
+    plugins {
+        id "org.jetbrains.kotlin.multiplatform" version "$kotlin_version"
+    }
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-java-toolchain/mppJvmWithJava/src/jvmWithJavaMain/kotlin/jvmWithJavaData/SomeJVMWithJavaClass.kt

@@ -0,0 +1,4 @@
+package jvmWithJavaData
+
+class SomeJVMWithJavaClass {
+}