diff --git a/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/group/StandardTestCaseGroupProvider.kt b/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/group/StandardTestCaseGroupProvider.kt
index bd58ef1b409..f33d9ba73e6 100644
--- a/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/group/StandardTestCaseGroupProvider.kt
+++ b/native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/group/StandardTestCaseGroupProvider.kt
@@ -230,12 +230,7 @@ internal class StandardTestCaseGroupProvider(private val settings: Settings) : T
                     val existingPackageName = firstMeaningfulLine?.getExistingPackageName()
                     if (existingPackageName != null) {
                         // Validate it.
-                        assertTrue(
-                            existingPackageName == basePackageName
-                                    || (existingPackageName.length > basePackageName.length
-                                    && existingPackageName.startsWith(basePackageName)
-                                    && existingPackageName[basePackageName.length] == '.')
-                        ) {
+                        assertTrue(existingPackageName.isSameOrSubpackageOf(basePackageName)) {
                             val location = Location(testDataFile, firstMeaningfulLine.number)
                             """
                                $location: Invalid package name declaration found: $firstMeaningfulLine