diff --git a/native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/support/TestDirectives.kt b/native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/support/TestDirectives.kt
index 05d37f8e7f8..6424f2c0ce6 100644
--- a/native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/support/TestDirectives.kt
+++ b/native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/support/TestDirectives.kt
@@ -215,6 +215,10 @@ internal enum class MutedOption {
     K2
 }
 
+internal val CINTEROP_SOURCE_EXTENSIONS = setOf("c", "cpp", "m", "mm")
+internal val CINTEROP_DEFINITION_EXTENSIONS = setOf("def", "h")
+internal val KNOWN_EXTENSIONS = setOf("kt") + CINTEROP_DEFINITION_EXTENSIONS + CINTEROP_SOURCE_EXTENSIONS
+
 internal class TestCInteropArgs(cinteropArgs: List<String>) : TestCompilerArgs(emptyList(), cinteropArgs) {
     constructor(vararg cinteropArgs: String) : this(cinteropArgs.asList())
 }
@@ -344,7 +348,7 @@ internal fun parseFileName(parsedDirective: RegisteredDirectivesParser.ParsedDir
         }
 
     val fileExtension = fileName.split(".").last()
-    if (fileExtension in setOf("kt", "def", "h", "c", "cpp", "m"))
+    if (fileExtension in KNOWN_EXTENSIONS)
         assertTrue(fileName.length > 3 && '/' !in fileName && '\\' !in fileName) {
             "$location: Invalid file name with extension $fileExtension in ${parsedDirective.directive} directive: $fileName"
         }
diff --git a/native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/support/compilation/TestCompilationFactory.kt b/native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/support/compilation/TestCompilationFactory.kt
index 0247cb62b28..8817460a356 100644
--- a/native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/support/compilation/TestCompilationFactory.kt
+++ b/native/native.tests/tests/org/jetbrains/kotlin/konan/test/blackbox/support/compilation/TestCompilationFactory.kt
@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.konan.test.blackbox.support.compilation
 
 import org.jetbrains.kotlin.container.topologicalSort
 import org.jetbrains.kotlin.konan.test.blackbox.muteCInteropTestIfNecessary
+import org.jetbrains.kotlin.konan.test.blackbox.support.CINTEROP_SOURCE_EXTENSIONS
 import org.jetbrains.kotlin.konan.test.blackbox.support.PackageName
 import org.jetbrains.kotlin.konan.test.blackbox.support.TestCase
 import org.jetbrains.kotlin.konan.test.blackbox.support.TestCase.*
@@ -216,7 +217,7 @@ internal class TestCompilationFactory {
                         muteCInteropTestIfNecessary(defFile, settings.get<KotlinNativeTargets>().testTarget)
 
                         val cSourceFiles = buildList {
-                            for (ext in listOf("cpp", "c", "m")) {
+                            for (ext in CINTEROP_SOURCE_EXTENSIONS) {
                                 filesByExtension[ext]?.let { addAll(it) }
                             }
                         }