[kotlin] J2K tests: optimize getFileTextWithErrors

Don't analyze the actual file for errors
if the expected testdata doesn't have errors.

GitOrigin-RevId: a5150153d30bf66197b8314ca5b0c4941e211cc7

plugins/kotlin/j2k/shared/tests/test/org/jetbrains/kotlin/j2k/AbstractJavaToKotlinConverterMultiFileTest.kt

@@ -83,7 +83,16 @@ abstract class AbstractJavaToKotlinConverterMultiFileTest : AbstractJavaToKotlin
         }
 
         for ((i, kotlinFile) in resultFiles.withIndex()) {
-            KotlinTestUtils.assertEqualsToFile(expectedResultFile(i), kotlinFile.getFileTextWithErrors())
+            val expectedFile = expectedResultFile(i)
+            val shouldCheckForErrors = expectedFile.readText().contains(ERROR_HEADER)
+            val actualText = if (shouldCheckForErrors) {
+                // Optimization: K2 `getFileTextWithErrors` is expensive
+                kotlinFile.getFileTextWithErrors()
+            } else {
+                kotlinFile.text
+            }
+
+            KotlinTestUtils.assertEqualsToFile(expectedFile, actualText)
         }
 
         for ((externalFile, externalPsiFile) in externalFiles.zip(externalPsiFiles)) {

plugins/kotlin/j2k/shared/tests/test/org/jetbrains/kotlin/j2k/AbstractJavaToKotlinConverterSingleFileTest.kt

@@ -49,13 +49,16 @@ abstract class AbstractJavaToKotlinConverterSingleFileTest : AbstractJavaToKotli
         val directives = KotlinTestUtils.parseDirectives(javaCode)
         val settings = configureSettings(directives)
         val convertedText = convertJavaToKotlin(prefix, javaCode, settings)
+        val expectedFile = File(javaFile.path.replace(".java", ".kt"))
+        val shouldCheckForErrors = expectedFile.readText().contains(ERROR_HEADER)
 
-        val actualText = if (prefix == "file") {
+        val actualText = if (prefix == "file" && shouldCheckForErrors) {
+            // Optimization: K2 `getFileTextWithErrors` is expensive
             createKotlinFile(convertedText).getFileTextWithErrors()
         } else {
             convertedText
         }
-        val expectedFile = File(javaFile.path.replace(".java", ".kt"))
+
         KotlinTestUtils.assertEqualsToFile(expectedFile, actualText)
     }
 

plugins/kotlin/j2k/shared/tests/test/org/jetbrains/kotlin/j2k/testUtils.kt

@@ -17,9 +17,11 @@ val J2K_PROJECT_DESCRIPTOR: KotlinWithJdkAndRuntimeLightProjectDescriptor =
         override fun getSdk(): Sdk = IdeaTestUtil.getMockJdk21()
     }
 
-val J2K_FULL_JDK_PROJECT_DESCRIPTOR: KotlinWithJdkAndRuntimeLightProjectDescriptor =
+internal val J2K_FULL_JDK_PROJECT_DESCRIPTOR: KotlinWithJdkAndRuntimeLightProjectDescriptor =
     KotlinWithJdkAndRuntimeLightProjectDescriptor.getInstanceFullJdk()
 
+internal const val ERROR_HEADER: String = "// ERROR"
+
 // TODO: adapted from `org.jetbrains.kotlin.idea.test.TestUtilsKt.dumpTextWithErrors`
 @OptIn(KtAllowAnalysisOnEdt::class)
 internal fun getK2FileTextWithErrors(file: KtFile): String {