[Gradle, JS] Add test on valid of webpack config

^KT-48273 fixed

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/Kotlin2JsGradlePluginIT.kt

@@ -965,6 +965,44 @@ abstract class AbstractKotlin2JsGradlePluginIT(val irBackend: Boolean) : BaseGra
             .let {
                 Gson().fromJson(it.readText(), PackageJson::class.java)
             }
+
+    @Test
+    fun testWebpackConfig() {
+        with(Project("kotlin-js-test-webpack-config")) {
+            setupWorkingDir()
+            gradleBuildScript().modify(::transformBuildScriptWithPluginsDsl)
+
+            build(
+                "browserDevelopmentWebpack"
+            ) {
+                assertSuccessful()
+            }
+
+            build(
+                "checkConfigDevelopmentWebpack",
+            ) {
+                assertSuccessful()
+            }
+
+            build(
+                "checkConfigProductionWebpack",
+            ) {
+                assertSuccessful()
+            }
+
+            build(
+                "checkConfigDevelopmentRun",
+            ) {
+                assertSuccessful()
+            }
+
+            build(
+                "checkConfigProductionRun",
+            ) {
+                assertSuccessful()
+            }
+        }
+    }
 }
 
 class GeneralKotlin2JsGradlePluginIT : BaseGradleIT() {

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-js-test-webpack-config/build.gradle.kts

@@ -0,0 +1,58 @@
+import org.jetbrains.kotlin.gradle.targets.js.npm.npmProject
+
+plugins {
+    kotlin("js") version "<pluginMarkerVersion>"
+}
+
+dependencies {
+    implementation(kotlin("stdlib-js"))
+}
+
+repositories {
+    mavenLocal()
+    mavenCentral()
+}
+
+kotlin {
+    js {
+        val compilation = compilations.getByName("main")
+        org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsExec.create(compilation, "checkConfigDevelopmentWebpack") {
+            inputFileProperty.set(provider { compilation.npmProject.require("webpack/bin/webpack.js") }.map { RegularFile { File(it) } })
+            dependsOn("browserDevelopmentWebpack")
+            val configFile = tasks.named<org.jetbrains.kotlin.gradle.targets.js.webpack.KotlinWebpack>("browserDevelopmentWebpack").map { it.configFile }.get()
+            configFile.parentFile.listFiles().forEach { println(it)}
+            args("configtest")
+            args(configFile.absolutePath)
+        }
+        org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsExec.create(compilation, "checkConfigProductionWebpack") {
+            inputFileProperty.set(provider { compilation.npmProject.require("webpack/bin/webpack.js") }.map { RegularFile { File(it) } })
+            dependsOn("browserProductionWebpack")
+            val configFile = tasks.named<org.jetbrains.kotlin.gradle.targets.js.webpack.KotlinWebpack>("browserProductionWebpack").map { it.configFile }.get()
+            args("configtest")
+            args(configFile.absolutePath)
+        }
+        org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsExec.create(compilation, "checkConfigDevelopmentRun") {
+            inputFileProperty.set(provider { compilation.npmProject.require("webpack/bin/webpack.js") }.map { RegularFile { File(it) } })
+            dependsOn("browserDevelopmentRun")
+            val configFile = tasks.named<org.jetbrains.kotlin.gradle.targets.js.webpack.KotlinWebpack>("browserDevelopmentRun").map { it.configFile }.get()
+            args("configtest")
+            args(configFile.absolutePath)
+        }
+        org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsExec.create(compilation, "checkConfigProductionRun") {
+            inputFileProperty.set(provider { compilation.npmProject.require("webpack/bin/webpack.js") }.map { RegularFile { File(it) } })
+            dependsOn("browserProductionRun")
+            val configFile = tasks.named<org.jetbrains.kotlin.gradle.targets.js.webpack.KotlinWebpack>("browserProductionRun").map { it.configFile }.get()
+            args("configtest")
+            args(configFile.absolutePath)
+        }
+        binaries.executable()
+        browser {
+            webpackTask {
+                generateConfigOnly = true
+            }
+            runTask {
+                generateConfigOnly = true
+            }
+        }
+    }
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-js-test-webpack-config/settings.gradle.kts

@@ -0,0 +1,8 @@
+pluginManagement {
+    repositories {
+        mavenLocal()
+        gradlePluginPortal()
+    }
+}
+
+rootProject.name = "kotlin-js-test-webpack-config"

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin-js-test-webpack-config/src/main/kotlin/Simple.kt

@@ -0,0 +1,6 @@
+
+fun main() {
+    console.log("Hello, ${greet()}")
+}
+
+fun greet() = "world"