[Test] Introduce two module structure transformers for codegen test

compiler/tests-common-new/tests/org/jetbrains/kotlin/test/services/ModuleTransformerForSwitchingBackend.kt

@@ -0,0 +1,37 @@
+/*
+ * 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.test.services
+
+import org.jetbrains.kotlin.test.TargetBackend
+import org.jetbrains.kotlin.test.TestInfrastructureInternals
+import org.jetbrains.kotlin.test.model.DependencyDescription
+import org.jetbrains.kotlin.test.model.DependencyKind
+import org.jetbrains.kotlin.test.model.DependencyRelation
+import org.jetbrains.kotlin.test.model.TestModule
+import org.jetbrains.kotlin.test.services.impl.TestModuleStructureImpl
+
+/**
+ * This transformers is used for transforming target backend
+ *   in tests with exactly two modules in it
+ */
+@TestInfrastructureInternals
+class ModuleTransformerForSwitchingBackend(
+    val backendForLib: TargetBackend,
+    val backendForMain: TargetBackend
+) : ModuleStructureTransformer() {
+    override fun transformModuleStructure(moduleStructure: TestModuleStructure): TestModuleStructure {
+        if (moduleStructure.modules.size != 2) error("Test should contain only one module")
+        val (first, second) = moduleStructure.modules
+
+        return TestModuleStructureImpl(
+            listOf(
+                first.copy(targetBackend = backendForLib),
+                second.copy(targetBackend = backendForMain)
+            ),
+            moduleStructure.originalTestDataFiles
+        )
+    }
+}

compiler/tests-common-new/tests/org/jetbrains/kotlin/test/services/ModuleTransformerForTwoFilesBoxTests.kt

@@ -0,0 +1,57 @@
+/*
+ * 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.test.services
+
+import org.jetbrains.kotlin.test.TestInfrastructureInternals
+import org.jetbrains.kotlin.test.model.DependencyDescription
+import org.jetbrains.kotlin.test.model.DependencyKind
+import org.jetbrains.kotlin.test.model.DependencyRelation
+import org.jetbrains.kotlin.test.model.TestModule
+import org.jetbrains.kotlin.test.services.impl.TestModuleStructureImpl
+
+/**
+ * This transformers is used for transforming test with two files
+ *   into test with two modules
+ *
+ * It will fail in case when module structure contains more than one module
+ *   or not exactly two files in it
+ */
+@TestInfrastructureInternals
+class ModuleTransformerForTwoFilesBoxTests : ModuleStructureTransformer() {
+    override fun transformModuleStructure(moduleStructure: TestModuleStructure): TestModuleStructure {
+        val module = moduleStructure.modules.singleOrNull() ?: error("Test should contain only one module")
+        val realFiles = module.files.filterNot { it.isAdditional }
+        if (realFiles.size != 2) error("Test should contain exactly two files")
+        val additionalFiles = module.files.filter { it.isAdditional }
+        val (first, second) = realFiles
+        val firstModule = TestModule(
+            name = "lib",
+            module.targetPlatform,
+            module.targetBackend,
+            module.frontendKind,
+            module.binaryKind,
+            files = listOf(first) + additionalFiles,
+            dependencies = emptyList(),
+            friends = emptyList(),
+            module.directives,
+            module.languageVersionSettings
+        )
+
+        val secondModule = TestModule(
+            name = "main",
+            module.targetPlatform,
+            module.targetBackend,
+            module.frontendKind,
+            module.binaryKind,
+            files = listOf(second) + additionalFiles,
+            dependencies = listOf(DependencyDescription("lib", DependencyKind.Binary, DependencyRelation.Dependency)),
+            friends = emptyList(),
+            module.directives,
+            module.languageVersionSettings
+        )
+        return TestModuleStructureImpl(listOf(firstModule, secondModule), moduleStructure.originalTestDataFiles)
+    }
+}