[Native][tests] Extract all external source-transformation logic into AbstractExternalNativeBlackBoxTest

This abstract class is used only for generated external codegen box tests that may have custom source transformers.

native/native.tests/tests/org/jetbrains/kotlin/generators/tests/GenerateNativeBlackboxTests.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.generators.tests
 
 import org.jetbrains.kotlin.generators.generateTestGroupSuiteWithJUnit5
 import org.jetbrains.kotlin.generators.model.annotation
+import org.jetbrains.kotlin.konan.blackboxtest.AbstractExternalNativeBlackBoxTest
 import org.jetbrains.kotlin.konan.blackboxtest.AbstractNativeBlackBoxTest
 import org.jetbrains.kotlin.konan.blackboxtest.support.group.UseExtTestCaseGroupProvider
 import org.jetbrains.kotlin.konan.blackboxtest.support.group.UseStandardTestCaseGroupProvider
@@ -19,7 +20,7 @@ fun main() {
     generateTestGroupSuiteWithJUnit5 {
         // External box tests.
         testGroup("native/native.tests/tests-gen", "compiler/testData") {
-            testClass<AbstractNativeBlackBoxTest>(
+            testClass<AbstractExternalNativeBlackBoxTest>(
                 suiteTestClassName = "ExternalTestGenerated",
                 annotations = listOf(external(), provider<UseExtTestCaseGroupProvider>())
             ) {

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/AbstractExternalNativeBlackBoxTest.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2010-2021 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.konan.blackboxtest
+
+import com.intellij.testFramework.TestDataFile
+import org.jetbrains.kotlin.konan.blackboxtest.support.util.ExternalSourceTransformer
+import org.jetbrains.kotlin.konan.blackboxtest.support.util.ExternalSourceTransformers
+import org.jetbrains.kotlin.konan.blackboxtest.support.util.ExternalSourceTransformersProvider
+import org.jetbrains.kotlin.konan.blackboxtest.support.util.ThreadSafeCache
+import org.jetbrains.kotlin.konan.blackboxtest.support.util.getAbsoluteFile
+import java.io.File
+
+abstract class AbstractExternalNativeBlackBoxTest : ExternalSourceTransformersProvider, AbstractNativeBlackBoxTest() {
+    private val registeredSourceTransformers: ThreadSafeCache<File, MutableList<ExternalSourceTransformer>> = ThreadSafeCache()
+
+    override fun getSourceTransformers(testDataFile: File): ExternalSourceTransformers? = registeredSourceTransformers[testDataFile]
+
+    /**
+     * Called directly from test class constructor.
+     */
+    fun register(@TestDataFile testDataFilePath: String, sourceTransformer: ExternalSourceTransformer) {
+        registeredSourceTransformers.computeIfAbsent(getAbsoluteFile(testDataFilePath)) { mutableListOf() } += sourceTransformer
+    }
+}

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/AbstractNativeBlackBoxTest.kt

@@ -7,31 +7,17 @@ package org.jetbrains.kotlin.konan.blackboxtest
 
 import com.intellij.testFramework.TestDataFile
 import org.jetbrains.kotlin.konan.blackboxtest.support.*
-import org.jetbrains.kotlin.konan.blackboxtest.support.PackageName
+import org.jetbrains.kotlin.konan.blackboxtest.support.util.TreeNode
-import org.jetbrains.kotlin.konan.blackboxtest.support.TestCaseId
+import org.jetbrains.kotlin.konan.blackboxtest.support.util.getAbsoluteFile
-import org.jetbrains.kotlin.konan.blackboxtest.support.TestRun
+import org.jetbrains.kotlin.konan.blackboxtest.support.util.joinPackageNames
-import org.jetbrains.kotlin.konan.blackboxtest.support.TestRunProvider
+import org.jetbrains.kotlin.konan.blackboxtest.support.util.prependPackageName
-import org.jetbrains.kotlin.konan.blackboxtest.support.util.*
 import org.junit.jupiter.api.DynamicNode
 import org.junit.jupiter.api.DynamicTest.dynamicTest
 import org.junit.jupiter.api.extension.ExtendWith
-import java.io.File
 
 @ExtendWith(NativeBlackBoxTestSupport::class)
 abstract class AbstractNativeBlackBoxTest {
     internal lateinit var testRunProvider: TestRunProvider
-    private val toBeRegistered = mutableListOf<Pair<File, List<(String) -> String>>>()
-    internal fun onRunProviderSet() {
-        for ((file, transformer) in toBeRegistered) {
-            testRunProvider.setProcessors(file, transformer)
-        }
-    }
-
-    fun register(@TestDataFile testDataFilePath: String, sourceTransformers: List<(String) -> String>) =
-        toBeRegistered.add(File(testDataFilePath) to sourceTransformers)
-
-    fun register(@TestDataFile testDataFilePath: String, sourceTransformer: (String) -> String) =
-        register(testDataFilePath, listOf(sourceTransformer))
 
     /**
      * Run JUnit test.

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/NativeBlackBoxTestSupport.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.test.TestMetadata
 import org.jetbrains.kotlin.test.services.JUnit5Assertions.assertEquals
 import org.jetbrains.kotlin.test.services.JUnit5Assertions.fail
 import org.jetbrains.kotlin.utils.addToStdlib.cast
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 import org.junit.jupiter.api.extension.BeforeAllCallback
 import org.junit.jupiter.api.extension.BeforeEachCallback
 import org.junit.jupiter.api.extension.ExtensionContext
@@ -32,7 +33,6 @@ class NativeBlackBoxTestSupport : BeforeEachCallback {
      */
     override fun beforeEach(extensionContext: ExtensionContext): Unit = with(extensionContext) {
         enclosingTestInstance.testRunProvider = getOrCreateTestRunProvider()
-        enclosingTestInstance.onRunProviderSet()
 
         // Set the essential compiler property.
         System.setProperty("kotlin.native.home", getOrCreateGlobalSettings().kotlinNativeHome.path)
@@ -46,9 +46,15 @@ class NativeBlackBoxTestSupport : BeforeEachCallback {
             val enclosingTestClass = enclosingTestClass
 
             return root.getStore(NAMESPACE).getOrComputeIfAbsent(enclosingTestClass.sanitizedName) {
-                val (testSettings, testSettingsAnnotation) = computeTestSettings(enclosingTestClass)
+                val computedTestSettings = computeTestSettings(enclosingTestClass)
-                val requiredSettings: Set<KClass<*>> =
+                val requiredSettings: Set<KClass<*>> = buildSet {
-                    /* Always required */ setOf(GlobalSettings::class, Binaries::class) +/* Custom */ testSettings.requiredSettings
+                    // Always required:
+                    this += GlobalSettings::class
+                    this += Binaries::class
+
+                    // Custom:
+                    addAll(computedTestSettings.testSettings.requiredSettings)
+                }
 
                 val globalSettings = getOrCreateGlobalSettings()
 
@@ -62,7 +68,7 @@ class NativeBlackBoxTestSupport : BeforeEachCallback {
                     }
                 })
 
-                val testCaseGroupProvider = createTestCaseGroupProvider(settings, testSettings, testSettingsAnnotation)
+                val testCaseGroupProvider = createTestCaseGroupProvider(settings, computedTestSettings, enclosingTestInstance)
 
                 TestRunProvider(settings, testCaseGroupProvider)
             }.cast()
@@ -80,11 +86,11 @@ class NativeBlackBoxTestSupport : BeforeEachCallback {
                 GlobalSettings()
             }.cast()
 
-        private fun computeTestSettings(enclosingTestClass: Class<*>): Pair<TestSettings, Annotation?> {
+        private fun computeTestSettings(enclosingTestClass: Class<*>): ComputedTestSettings {
-            val findTestSettings: Class<*>.() -> Pair<TestSettings, Annotation>? = {
+            val findTestSettings: Class<*>.() -> ComputedTestSettings? = {
                 annotations.asSequence().mapNotNull { annotation ->
                     val testSettings = annotation.annotationClass.findAnnotation<TestSettings>() ?: return@mapNotNull null
-                    testSettings to annotation
+                    ComputedTestSettings(testSettings, annotation)
                 }.firstOrNull()
             }
 
@@ -147,29 +153,29 @@ class NativeBlackBoxTestSupport : BeforeEachCallback {
 
         private fun createTestCaseGroupProvider(
             settings: Settings,
-            testSettings: TestSettings,
+            computedTestSettings: ComputedTestSettings,
-            testSettingsAnnotation: Annotation?
+            enclosingTestInstance: AbstractNativeBlackBoxTest
         ): TestCaseGroupProvider {
-            // Try to find a constructor that accepts the setting and the annotation.
+            val (testSettings: TestSettings, testSettingsAnnotation: Annotation?) = computedTestSettings
-            if (testSettingsAnnotation != null) {
+            val providerClass: KClass<out TestCaseGroupProvider> = testSettings.providerClass
-                val testSettingsAnnotationClass = testSettingsAnnotation.annotationClass
+
-                testSettings.providerClass.constructors.asSequence()
+            // Assumption: For simplicity’s sake TestCaseGroupProvider has just one constructor.
-                    .forEach { c ->
+            val constructor = providerClass.constructors.singleOrNull()
-                        val (p1, p2) = c.parameters.takeIf { it.size == 2 } ?: return@forEach
+                ?: fail { "No or multiple constructors found for $providerClass" }
-                        if (p1.hasTypeOf<Settings>() && p2.hasTypeOf(testSettingsAnnotationClass))
+
-                            return c.call(settings, testSettingsAnnotation).cast()
+            val testSettingsAnnotationClass: KClass<out Annotation>? = testSettingsAnnotation?.annotationClass
-                    }
+            val sourceTransformersProvider = enclosingTestInstance.safeAs<ExternalSourceTransformersProvider>()
+
+            val arguments = constructor.parameters.map { parameter ->
+                when {
+                    parameter.hasTypeOf<Settings>() -> settings
+                    sourceTransformersProvider != null && parameter.hasTypeOf<ExternalSourceTransformersProvider>() -> sourceTransformersProvider
+                    testSettingsAnnotationClass != null && parameter.hasTypeOf(testSettingsAnnotationClass) -> testSettingsAnnotation
+                    else -> fail { "Can't provide all arguments for $constructor" }
+                }
             }
 
-            // ... or the settings at least.
+            return constructor.call(*arguments.toTypedArray()).cast()
-            testSettings.providerClass.constructors.asSequence()
-                .forEach { c ->
-                    val p = c.parameters.singleOrNull() ?: return@forEach
-                    if (p.hasTypeOf<Settings>())
-                        return c.call(settings).cast()
-                }
-
-            fail { "No suitable constructor for ${testSettings.providerClass}" }
         }
 
         private inline fun <reified T : Any> KParameter.hasTypeOf(): Boolean = hasTypeOf(T::class)
@@ -178,3 +184,5 @@ class NativeBlackBoxTestSupport : BeforeEachCallback {
         private val TestMetadata.testRoot: File get() = getAbsoluteFile(localPath = value)
     }
 }
+
+private data class ComputedTestSettings(val testSettings: TestSettings, val annotation: Annotation?)

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/TestRunProvider.kt

@@ -17,15 +17,14 @@ import org.jetbrains.kotlin.konan.blackboxtest.support.runner.LocalTestNameExtra
 import org.jetbrains.kotlin.konan.blackboxtest.support.runner.LocalTestRunner
 import org.jetbrains.kotlin.konan.blackboxtest.support.settings.GlobalSettings
 import org.jetbrains.kotlin.konan.blackboxtest.support.settings.Settings
-import org.jetbrains.kotlin.konan.blackboxtest.support.util.*
 import org.jetbrains.kotlin.konan.blackboxtest.support.util.ThreadSafeCache
 import org.jetbrains.kotlin.konan.blackboxtest.support.util.TreeNode
 import org.jetbrains.kotlin.konan.blackboxtest.support.util.buildTree
+import org.jetbrains.kotlin.konan.blackboxtest.support.util.startsWith
 import org.jetbrains.kotlin.test.services.JUnit5Assertions.assertTrue
 import org.jetbrains.kotlin.test.services.JUnit5Assertions.fail
 import org.junit.jupiter.api.Assumptions.assumeTrue
 import org.junit.jupiter.api.extension.ExtensionContext
-import java.io.File
 
 internal class TestRunProvider(
     private val settings: Settings,
@@ -35,10 +34,6 @@ internal class TestRunProvider(
     private val cachedCompilations = ThreadSafeCache<TestCompilationCacheKey, TestCompilation>()
     private val cachedTestNames = ThreadSafeCache<TestCompilationCacheKey, Collection<TestName>>()
 
-    fun setProcessors(testDataFile: File, sourceTransformers: List<(String) -> String>) {
-        testCaseGroupProvider.setPreprocessors(testDataFile, sourceTransformers)
-    }
-
     /**
      * Produces a single [TestRun] per [TestCase]. So-called "one test case/one test run" mode.
      *

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/group/ExtTestCaseGroupProvider.kt

@@ -41,9 +41,9 @@ import org.jetbrains.kotlin.utils.addToStdlib.cast
 import java.io.File
 
 internal class ExtTestCaseGroupProvider(
-    private val settings: Settings
+    private val settings: Settings,
+    private val sourceTransformersProvider: ExternalSourceTransformersProvider
 ) : TestCaseGroupProvider, TestDisposable(parentDisposable = settings) {
-    private val sourceTransformers: MutableMap<String, List<(String) -> String>> = mutableMapOf()
     private val structureFactory = ExtTestDataFileStructureFactory(parentDisposable = this)
     private val sharedModules = ThreadSafeCache<String, TestModule.Shared?>()
 
@@ -61,9 +61,7 @@ internal class ExtTestCaseGroupProvider(
         val testCases = mutableListOf<TestCase>()
 
         testDataFiles.forEach { testDataFile ->
-            val extTestDataFile = ExtTestDataFile(
+            val extTestDataFile = ExtTestDataFile(settings, structureFactory, sourceTransformersProvider, testDataFile)
-                settings, structureFactory, testDataFile, sourceTransformers[testDataFile.canonicalPath] ?: listOf()
-            )
 
             if (extTestDataFile.isRelevant)
                 testCases += extTestDataFile.createTestCase(
@@ -77,13 +75,6 @@ internal class ExtTestCaseGroupProvider(
         TestCaseGroup.Default(disabledTestCaseIds, testCases)
     }
 
-    override fun setPreprocessors(testDataDir: File, preprocessors: List<(String) -> String>) {
-        if (preprocessors.isNotEmpty())
-            sourceTransformers[testDataDir.canonicalPath] = preprocessors
-        else
-            sourceTransformers.remove(testDataDir.canonicalPath)
-    }
-
     override fun getTestCaseGroup(testCaseGroupId: TestCaseGroupId): TestCaseGroup? {
         assertNotDisposed()
         assertTrue(testCaseGroupId is TestCaseGroupId.TestDataDir)
@@ -133,15 +124,17 @@ internal class ExtTestCaseGroupProvider(
 private class ExtTestDataFile(
     private val settings: Settings,
     structureFactory: ExtTestDataFileStructureFactory,
-    private val testDataFile: File,
+    sourceTransformersProvider: ExternalSourceTransformersProvider,
-    sourceTransformers: List<(String) -> String>
+    private val testDataFile: File
 ) {
     private val structure by lazy {
-        structureFactory.ExtTestDataFileStructure(testDataFile, sourceTransformers) { line ->
+        val customTransformers: ExternalSourceTransformers? = sourceTransformersProvider.getSourceTransformers(testDataFile)
-            // Remove all diagnostic parameters from the text. Examples:
+        val allTransformers: ExternalSourceTransformers = if (customTransformers.isNullOrEmpty())
-            //   <!NO_TAIL_CALLS_FOUND!>, <!NON_TAIL_RECURSIVE_CALL!>, <!>.
+            MANDATORY_SOURCE_TRANSFORMERS
-            line.replace(DIAGNOSTIC_REGEX) { match -> match.groupValues[1] }
+        else
-        }
+            MANDATORY_SOURCE_TRANSFORMERS + customTransformers
+
+        structureFactory.ExtTestDataFileStructure(testDataFile, allTransformers)
     }
 
     private val testDataFileSettings by lazy {
@@ -633,14 +626,14 @@ private class ExtTestDataFile(
         private fun Directives.multiValues(key: String, predicate: (String) -> Boolean = { true }): Set<String> =
             listValues(key)?.flatMap { it.split(' ') }?.filter(predicate)?.toSet().orEmpty()
 
-        private val DIAGNOSTIC_REGEX = Regex("<!.*?!>(.*?)<!>")
-
         private const val THREAD_LOCAL_ANNOTATION = "@kotlin.native.ThreadLocal"
 
         private val BOX_FUNCTION_NAME = Name.identifier("box")
         private val OPT_IN_ANNOTATION_NAME = Name.identifier("OptIn")
         private val HELPERS_PACKAGE_NAME = Name.identifier("helpers")
         private val TYPE_OF_NAME = Name.identifier("typeOf")
+
+        private val MANDATORY_SOURCE_TRANSFORMERS: ExternalSourceTransformers = listOf(DiagnosticsRemovingSourceTransformer)
     }
 }
 
@@ -659,16 +652,12 @@ private typealias SharedModuleCache = (moduleName: String, generator: SharedModu
 private class ExtTestDataFileStructureFactory(parentDisposable: Disposable) : TestDisposable(parentDisposable) {
     private val psiFactory = createPsiFactory(parentDisposable = this)
 
-    inner class ExtTestDataFileStructure(
+    inner class ExtTestDataFileStructure(originalTestDataFile: File, sourceTransformers: ExternalSourceTransformers) {
-        originalTestDataFile: File,
-        sourceTransformers: List<(String) -> String>,
-        initialCleanUpTransformation: (String) -> String
-    ) {
         init {
             assertNotDisposed()
         }
 
-        private val filesAndModules = FilesAndModules(originalTestDataFile, initialCleanUpTransformation, sourceTransformers)
+        private val filesAndModules = FilesAndModules(originalTestDataFile, sourceTransformers)
 
         val directives: Directives get() = filesAndModules.directives
 
@@ -824,16 +813,12 @@ private class ExtTestDataFileStructureFactory(parentDisposable: Disposable) : Te
             ExtTestModule(name, dependencies, friends)
     }
 
-    private inner class FilesAndModules(
+    private inner class FilesAndModules(originalTestDataFile: File, sourceTransformers: ExternalSourceTransformers) {
-        originalTestDataFile: File,
-        initialCleanUpTransformation: (String) -> String,
-        sourceTransformers: List<(String) -> String>
-    ) {
         private val testFileFactory = ExtTestFileFactory()
 
         private val generatedFiles = TestFiles.createTestFiles(
             /* testFileName = */ DEFAULT_FILE_NAME,
-            /* expectedText = */ originalTestDataFile.applySourceTransformers(sourceTransformers),
+            /* expectedText = */ originalTestDataFile.readText(),
             /* factory = */ testFileFactory,
             /* preserveLocations = */ true
         )
@@ -842,7 +827,7 @@ private class ExtTestDataFileStructureFactory(parentDisposable: Disposable) : Te
             // Clean up contents of every individual test file. Important: This should be done only after parsing testData file,
             // because parsing of testData file relies on certain directives which could be removed by the transformation.
             generatedFiles.forEach { file ->
-                file.text = file.text.lineSequence().joinToString("\n", transform = initialCleanUpTransformation)
+                file.text = sourceTransformers.fold(file.text) { source, transformer -> transformer(source) }
             }
 
             val modules = generatedFiles.map { it.module }.associateBy { it.name }

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/group/PredefinedTestCaseGroupProvider.kt

@@ -65,10 +65,6 @@ internal class PredefinedTestCaseGroupProvider(private val settings: Settings, a
         TestCaseGroup.Default(disabledTestCaseIds = emptySet(), testCases = listOf(testCase))
     }
 
-    override fun setPreprocessors(testDataDir: File, preprocessors: List<(String) -> String>) {
-        // do nothing
-    }
-
     override fun getTestCaseGroup(testCaseGroupId: TestCaseGroupId): TestCaseGroup? {
         assertTrue(testCaseGroupId is TestCaseGroupId.Named)
         return lazyTestCaseGroups[testCaseGroupId.cast()]

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/group/StandardTestCaseGroupProvider.kt

@@ -12,10 +12,6 @@ import org.jetbrains.kotlin.konan.blackboxtest.support.settings.GeneratedSources
 import org.jetbrains.kotlin.konan.blackboxtest.support.settings.Settings
 import org.jetbrains.kotlin.konan.blackboxtest.support.settings.TestRoots
 import org.jetbrains.kotlin.konan.blackboxtest.support.util.*
-import org.jetbrains.kotlin.konan.blackboxtest.support.util.DEFAULT_FILE_NAME
-import org.jetbrains.kotlin.konan.blackboxtest.support.util.ThreadSafeFactory
-import org.jetbrains.kotlin.konan.blackboxtest.support.util.computeGeneratedSourcesDir
-import org.jetbrains.kotlin.konan.blackboxtest.support.util.computePackageName
 import org.jetbrains.kotlin.test.directives.model.Directive
 import org.jetbrains.kotlin.test.services.JUnit5Assertions
 import org.jetbrains.kotlin.test.services.JUnit5Assertions.assertEquals
@@ -45,13 +41,6 @@ internal class StandardTestCaseGroupProvider(private val settings: Settings) : T
         TestCaseGroup.Default(disabledTestCaseIds = emptySet(), testCases = testCases)
     }
 
-    override fun setPreprocessors(testDataDir: File, preprocessors: List<(String) -> String>) {
-        if (preprocessors.isNotEmpty())
-            sourceTransformers[testDataDir.canonicalPath] = preprocessors
-        else
-            sourceTransformers.remove(testDataDir.canonicalPath)
-    }
-
     override fun getTestCaseGroup(testCaseGroupId: TestCaseGroupId): TestCaseGroup? {
         assertTrue(testCaseGroupId is TestCaseGroupId.TestDataDir)
         return lazyTestCaseGroups[testCaseGroupId.cast()]
@@ -101,7 +90,7 @@ internal class StandardTestCaseGroupProvider(private val settings: Settings) : T
         fun finishTestFile(forceFinish: Boolean, location: Location) {
             val needToFinish = forceFinish
                     || currentTestFileName != null
-                    || (currentTestFileName == null /*&& testFiles.isEmpty()*/ && currentTestFileText.hasAnythingButComments())
+                    || (/*currentTestFileName == null && testFiles.isEmpty() &&*/ currentTestFileText.hasAnythingButComments())
 
             if (needToFinish) {
                 val fileName = currentTestFileName ?: DEFAULT_FILE_NAME
@@ -119,8 +108,7 @@ internal class StandardTestCaseGroupProvider(private val settings: Settings) : T
             }
         }
 
-        val text = testDataFile.applySourceTransformers(sourceTransformers[testDataFile.canonicalPath] ?: listOf())
+        testDataFile.readLines().forEachIndexed { lineNumber, line ->
-        text.lines().forEachIndexed { lineNumber, line ->
             val location = Location(testDataFile, lineNumber)
             val expectFileDirectiveAfterModuleDirective =
                 lastParsedDirective == TestDirectives.MODULE // Only FILE directive may follow MODULE directive.

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/group/TestCaseGroupProvider.kt

@@ -7,15 +7,7 @@ package org.jetbrains.kotlin.konan.blackboxtest.support.group
 
 import org.jetbrains.kotlin.konan.blackboxtest.support.TestCaseGroup
 import org.jetbrains.kotlin.konan.blackboxtest.support.TestCaseGroupId
-import java.io.File
 
 internal interface TestCaseGroupProvider {
-    fun setPreprocessors(testDataDir: File, preprocessors: List<(String) -> String>)
     fun getTestCaseGroup(testCaseGroupId: TestCaseGroupId): TestCaseGroup?
-}
+}
-
-internal fun String.applySourceTransformers(sourceTransformers: List<(String) -> String>) =
-    sourceTransformers.fold(this) { source, transformer -> transformer(source) }
-
-internal fun File.applySourceTransformers(sourceTransformers: List<(String) -> String>) =
-    readText().applySourceTransformers(sourceTransformers)

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/util/ExternalSourcesTransformation.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2010-2021 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.konan.blackboxtest.support.util
+
+import org.jetbrains.kotlin.konan.blackboxtest.AbstractExternalNativeBlackBoxTest
+import java.io.File
+
+/**
+ * This relates only to external codegen tests (see [AbstractExternalNativeBlackBoxTest]) that may have their own source transformers.
+ */
+
+internal typealias ExternalSourceTransformer = (/* file contents */ String) -> /* patched file contents */ String
+internal typealias ExternalSourceTransformers = List<ExternalSourceTransformer>
+
+internal interface ExternalSourceTransformersProvider {
+    fun getSourceTransformers(testDataFile: File): ExternalSourceTransformers?
+}
+
+internal object DiagnosticsRemovingSourceTransformer : ExternalSourceTransformer {
+    override fun invoke(source: String) = source.lineSequence().joinToString("\n") { line ->
+        // Remove all diagnostic parameters from the text. Examples:
+        //   <!NO_TAIL_CALLS_FOUND!>, <!NON_TAIL_RECURSIVE_CALL!>, <!>.
+        line.replace(DIAGNOSTIC_REGEX) { match -> match.groupValues[1] }
+    }
+
+    private val DIAGNOSTIC_REGEX = Regex("<!.*?!>(.*?)<!>")
+}