Minor: Extract findElementByComment() function

compiler/tests/org/jetbrains/kotlin/test/util/jetTestUtils.kt

@@ -18,6 +18,11 @@ package org.jetbrains.kotlin.test.util
 
 import com.intellij.testFramework.fixtures.CodeInsightTestFixture
 import com.intellij.openapi.util.io.FileUtil
+import com.intellij.psi.PsiComment
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiWhiteSpace
+import com.intellij.psi.util.PsiTreeUtil
+import org.jetbrains.kotlin.psi.*
 import java.io.File
 
 public fun String.trimTrailingWhitespacesAndAddNewlineAtEOF(): String =
@@ -62,3 +67,29 @@ public fun String.trimIndent(): String {
         }
     }.joinToString(separator = "\n")
 }
+
+public fun JetFile.findElementByComment(commentText: String): JetElement? {
+    var result: JetElement? = null
+    accept(
+            object : JetTreeVisitorVoid() {
+                override fun visitComment(comment: PsiComment) {
+                    if (comment.getText() == commentText) {
+                        val parent = comment.getParent()
+                        if (parent is JetDeclaration) {
+                            result = parent
+                        }
+                        else {
+                            result = PsiTreeUtil.skipSiblingsForward(
+                                    comment,
+                                    javaClass<PsiWhiteSpace>(),
+                                    javaClass<PsiComment>(),
+                                    javaClass<JetPackageDirective>()
+                            ) as? JetElement
+                        }
+                    }
+                }
+            }
+    )
+
+    return result
+}

idea/tests/org/jetbrains/kotlin/idea/refactoring/introduce/AbstractJetExtractionTest.kt

@@ -39,6 +39,7 @@ import org.jetbrains.kotlin.renderer.DescriptorRenderer
 import org.jetbrains.kotlin.test.ConfigLibraryUtil
 import org.jetbrains.kotlin.test.InTextDirectivesUtils
 import org.jetbrains.kotlin.test.JetTestUtils
+import org.jetbrains.kotlin.test.util.findElementByComment
 import org.jetbrains.kotlin.utils.emptyOrSingletonList
 import java.io.File
 import java.util.Collections
@@ -87,28 +88,7 @@ public abstract class AbstractJetExtractionTest() : JetLightCodeInsightFixtureTe
 
     protected fun doExtractFunctionTest(path: String) {
         doTest(path) { file ->
-            var explicitPreviousSibling: PsiElement? = null
+            val explicitPreviousSibling = file.findElementByComment("// SIBLING:")
-            file.accept(
-                    object: JetTreeVisitorVoid() {
-                        override fun visitComment(comment: PsiComment) {
-                            if (comment.getText() == "// SIBLING:") {
-                                val parent = comment.getParent()
-                                if (parent is JetDeclaration) {
-                                    explicitPreviousSibling = parent
-                                }
-                                else {
-                                    explicitPreviousSibling = PsiTreeUtil.skipSiblingsForward(
-                                            comment,
-                                            javaClass<PsiWhiteSpace>(),
-                                            javaClass<PsiComment>(),
-                                            javaClass<JetPackageDirective>()
-                                    )
-                                }
-                            }
-                        }
-                    }
-            )
-
             val fileText = file.getText() ?: ""
             val expectedNames = InTextDirectivesUtils.findListWithPrefixes(fileText, "// SUGGESTED_NAMES: ")
             val expectedDescriptors =