diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/JSServiceMessages.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/JSServiceMessages.kt
new file mode 100644
index 00000000000..a6d06bf5bf8
--- /dev/null
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/JSServiceMessages.kt
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.targets.js.testing
+
+import org.gradle.api.internal.tasks.testing.TestResultProcessor
+import org.gradle.process.ProcessForkOptions
+import org.jetbrains.kotlin.gradle.internal.testing.TCServiceMessagesClient
+import org.jetbrains.kotlin.gradle.internal.testing.TCServiceMessagesClientSettings
+import org.jetbrains.kotlin.gradle.internal.testing.TCServiceMessagesTestExecutionSpec
+import org.slf4j.Logger
+
+internal open class JSServiceMessagesTestExecutionSpec(
+    forkOptions: ProcessForkOptions,
+    args: List<String>,
+    checkExitCode: Boolean,
+    clientSettings: TCServiceMessagesClientSettings
+) : TCServiceMessagesTestExecutionSpec(
+    forkOptions,
+    args,
+    checkExitCode,
+    clientSettings
+) {
+    protected val suppressedOutput = StringBuilder()
+
+    override fun showSuppressedOutput() {
+        println(suppressedOutput)
+    }
+
+    override fun createClient(testResultProcessor: TestResultProcessor, log: Logger): TCServiceMessagesClient {
+        return JSServiceMessagesClient(
+            results = testResultProcessor,
+            settings = clientSettings,
+            log = log,
+            suppressedOutput = suppressedOutput
+        )
+    }
+}
+
+internal open class JSServiceMessagesClient(
+    results: TestResultProcessor,
+    settings: TCServiceMessagesClientSettings,
+    log: Logger,
+    private val suppressedOutput: StringBuilder
+) : TCServiceMessagesClient(results, settings, log) {
+    override fun printNonTestOutput(text: String) {
+        suppressedOutput.appendln(text)
+    }
+}
\ No newline at end of file
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/JSServiceMessagesClient.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/JSServiceMessagesClient.kt
deleted file mode 100644
index 9355fd01eea..00000000000
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/JSServiceMessagesClient.kt
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package org.jetbrains.kotlin.gradle.targets.js.testing
-
-import org.gradle.api.internal.tasks.testing.TestResultProcessor
-import org.jetbrains.kotlin.gradle.internal.testing.TCServiceMessagesClient
-import org.jetbrains.kotlin.gradle.internal.testing.TCServiceMessagesClientSettings
-import org.slf4j.Logger
-
-internal class JSServiceMessagesClient(
-    results: TestResultProcessor,
-    settings: TCServiceMessagesClientSettings,
-    log: Logger
-) : TCServiceMessagesClient(results, settings, log) {
-    override fun printNonTestOutput(text: String) {
-        // do nothing
-    }
-}
\ No newline at end of file
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/karma/KotlinKarma.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/karma/KotlinKarma.kt
index 4e4ae178ec1..46b5945cffa 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/karma/KotlinKarma.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/karma/KotlinKarma.kt
@@ -12,7 +12,6 @@ import org.gradle.api.internal.tasks.testing.TestResultProcessor
 import org.gradle.internal.logging.progress.ProgressLogger
 import org.gradle.process.ProcessForkOptions
 import org.jetbrains.kotlin.gradle.internal.operation
-import org.jetbrains.kotlin.gradle.internal.testing.TCServiceMessagesClient
 import org.jetbrains.kotlin.gradle.internal.testing.TCServiceMessagesClientSettings
 import org.jetbrains.kotlin.gradle.internal.testing.TCServiceMessagesTestExecutionSpec
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinJsCompilation
@@ -22,9 +21,7 @@ import org.jetbrains.kotlin.gradle.targets.js.appendConfigsFromDir
 import org.jetbrains.kotlin.gradle.targets.js.internal.parseNodeJsStackTraceAsJvm
 import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootPlugin
 import org.jetbrains.kotlin.gradle.targets.js.npm.npmProject
-import org.jetbrains.kotlin.gradle.targets.js.testing.KotlinJsTest
-import org.jetbrains.kotlin.gradle.targets.js.testing.KotlinJsTestFramework
-import org.jetbrains.kotlin.gradle.targets.js.testing.KotlinTestRunnerCliArgs
+import org.jetbrains.kotlin.gradle.targets.js.testing.*
 import org.jetbrains.kotlin.gradle.targets.js.webpack.KotlinWebpackConfig
 import org.jetbrains.kotlin.gradle.testing.internal.reportsDir
 import org.slf4j.Logger
@@ -418,14 +415,13 @@ class KotlinKarma(override val compilation: KotlinJsCompilation) : KotlinJsTestF
                 nodeModules.map { npmProject.require(it) } +
                 listOf("start", karmaConfJs.absolutePath, "--debug")
 
-        return object : TCServiceMessagesTestExecutionSpec(
+        return object : JSServiceMessagesTestExecutionSpec(
             forkOptions,
             args,
             false,
             clientSettings
         ) {
             lateinit var progressLogger: ProgressLogger
-            val suppressedOutput = StringBuilder()
 
             var isLaunchFailed: Boolean = false
 
@@ -441,12 +437,13 @@ class KotlinKarma(override val compilation: KotlinJsCompilation) : KotlinJsTestF
                 }
             }
 
-            override fun showSuppressedOutput() {
-                println(suppressedOutput)
-            }
-
             override fun createClient(testResultProcessor: TestResultProcessor, log: Logger) =
-                object : TCServiceMessagesClient(testResultProcessor, clientSettings, log) {
+                object : JSServiceMessagesClient(
+                    testResultProcessor,
+                    clientSettings,
+                    log,
+                    suppressedOutput
+                ) {
                     val baseTestNameSuffix get() = settings.testNameSuffix
                     override var testNameSuffix: String? = baseTestNameSuffix
 
@@ -490,7 +487,7 @@ class KotlinKarma(override val compilation: KotlinJsCompilation) : KotlinJsTestF
                             return
                         }
 
-                        suppressedOutput.appendln(text)
+                        super.printNonTestOutput(text)
                     }
                 }
         }
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/nodejs/KotlinNodeJsTestRunner.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/nodejs/KotlinNodeJsTestRunner.kt
index 2c905df70d6..1a4f45865cc 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/nodejs/KotlinNodeJsTestRunner.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/testing/nodejs/KotlinNodeJsTestRunner.kt
@@ -6,9 +6,7 @@
 package org.jetbrains.kotlin.gradle.targets.js.testing.nodejs
 
 import org.gradle.api.Project
-import org.gradle.api.internal.tasks.testing.TestResultProcessor
 import org.gradle.process.ProcessForkOptions
-import org.jetbrains.kotlin.gradle.internal.testing.TCServiceMessagesClient
 import org.jetbrains.kotlin.gradle.internal.testing.TCServiceMessagesClientSettings
 import org.jetbrains.kotlin.gradle.internal.testing.TCServiceMessagesTestExecutionSpec
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinJsCompilation
@@ -16,12 +14,11 @@ import org.jetbrains.kotlin.gradle.targets.js.KotlinGradleNpmPackage
 import org.jetbrains.kotlin.gradle.targets.js.RequiredKotlinJsDependency
 import org.jetbrains.kotlin.gradle.targets.js.internal.parseNodeJsStackTraceAsJvm
 import org.jetbrains.kotlin.gradle.targets.js.npm.npmProject
-import org.jetbrains.kotlin.gradle.targets.js.testing.JSServiceMessagesClient
+import org.jetbrains.kotlin.gradle.targets.js.testing.JSServiceMessagesTestExecutionSpec
 import org.jetbrains.kotlin.gradle.targets.js.testing.KotlinJsTest
 import org.jetbrains.kotlin.gradle.targets.js.testing.KotlinJsTestFramework
 import org.jetbrains.kotlin.gradle.targets.js.testing.KotlinTestRunnerCliArgs
 import org.jetbrains.kotlin.gradle.testing.IgnoredTestSuites
-import org.slf4j.Logger
 
 class KotlinNodeJsTestRunner(override val compilation: KotlinJsCompilation) : KotlinJsTestFramework {
     val project: Project
@@ -67,19 +64,11 @@ class KotlinNodeJsTestRunner(override val compilation: KotlinJsCompilation) : Ko
                 } +
                 cliArgs.toList()
 
-        return object : TCServiceMessagesTestExecutionSpec(
+        return JSServiceMessagesTestExecutionSpec(
             forkOptions,
             args,
             true,
             clientSettings
-        ) {
-            override fun createClient(testResultProcessor: TestResultProcessor, log: Logger): TCServiceMessagesClient {
-                return JSServiceMessagesClient(
-                    testResultProcessor,
-                    clientSettings,
-                    log
-                )
-            }
-        }
+        )
     }
 }
\ No newline at end of file