diff --git a/compiler/testData/diagnostics/helpers/types/checkType.kt b/compiler/testData/diagnostics/helpers/types/checkType.kt
new file mode 100644
index 00000000000..1e4869bc28b
--- /dev/null
+++ b/compiler/testData/diagnostics/helpers/types/checkType.kt
@@ -0,0 +1,7 @@
+package tests._checkType
+
+fun <T> checkSubtype(t: T) = t
+class Inv<T>
+fun <E> Inv<E>._() {}
+
+infix fun <T> T.checkType(f: Inv<T>.() -> Unit) {}
diff --git a/compiler/tests-common/tests/org/jetbrains/kotlin/checkers/BaseDiagnosticsTest.kt b/compiler/tests-common/tests/org/jetbrains/kotlin/checkers/BaseDiagnosticsTest.kt
index 3a82fab0568..6ed701881be 100644
--- a/compiler/tests-common/tests/org/jetbrains/kotlin/checkers/BaseDiagnosticsTest.kt
+++ b/compiler/tests-common/tests/org/jetbrains/kotlin/checkers/BaseDiagnosticsTest.kt
@@ -100,7 +100,9 @@ abstract class BaseDiagnosticsTest : KotlinMultiFileTestWithJava<TestModule, Tes
                 ktFiles.add(KotlinTestUtils.createFile("EXPLICIT_FLEXIBLE_TYPES.kt", EXPLICIT_FLEXIBLE_TYPES_DECLARATIONS, project))
             }
             if (declareCheckType) {
-                ktFiles.add(KotlinTestUtils.createFile("CHECK_TYPE.kt", CHECK_TYPE_DECLARATIONS, project))
+                val checkTypeDeclarations = File("$HELPERS_PATH/types/checkType.kt").readText()
+
+                ktFiles.add(KotlinTestUtils.createFile("CHECK_TYPE.kt", checkTypeDeclarations, project))
             }
         }
 
@@ -338,6 +340,7 @@ abstract class BaseDiagnosticsTest : KotlinMultiFileTestWithJava<TestModule, Tes
     }
 
     companion object {
+        private const val HELPERS_PATH = "./compiler/testData/diagnostics/helpers"
         val DIAGNOSTICS_DIRECTIVE = "DIAGNOSTICS"
         val DIAGNOSTICS_PATTERN: Pattern = Pattern.compile("([\\+\\-!])(\\w+)\\s*")
         val DIAGNOSTICS_TO_INCLUDE_ANYWAY: Set<DiagnosticFactory<*>> = setOf(
@@ -355,11 +358,6 @@ abstract class BaseDiagnosticsTest : KotlinMultiFileTestWithJava<TestModule, Tes
 
         val CHECK_TYPE_DIRECTIVE = "CHECK_TYPE"
         val CHECK_TYPE_PACKAGE = "tests._checkType"
-        private val CHECK_TYPE_DECLARATIONS = "\npackage " + CHECK_TYPE_PACKAGE +
-                "\nfun <T> checkSubtype(t: T) = t" +
-                "\nclass Inv<T>" +
-                "\nfun <E> Inv<E>._() {}" +
-                "\ninfix fun <T> T.checkType(f: Inv<T>.() -> Unit) {}"
         val CHECK_TYPE_IMPORT = "import $CHECK_TYPE_PACKAGE.*"
 
         val EXPLICIT_FLEXIBLE_TYPES_DIRECTIVE = "EXPLICIT_FLEXIBLE_TYPES"