Add function to make a snapshot of current test project

This will allow checking current state of test project and try
to work with it directly.

^KT-45745 In Progress

libraries/tools/kotlin-gradle-plugin-integration-tests/Readme.md

@@ -88,7 +88,7 @@ add a new assertion, add as a reviewer someone from Kotlin build tools team.
 
 ##### Additional test helpers
 
-Whenever you need to test combination of different JDKs and Gradle versions - you could use `@GradleWithJdkTest` instead of `@GradleTest`. 
+- Whenever you need to test combination of different JDKs and Gradle versions - you could use `@GradleWithJdkTest` instead of `@GradleTest`. 
 Then test method will receive requires JDKs as a second parameter:
 ```kotlin
 @JdkVersions(version = [JavaVersion.VERSION_11, JavaVersion.VERSION_17])
@@ -103,6 +103,8 @@ fun someTest(
 }
 ```
 
+- If you want to copy current state of the test project and play with it separately - you could use `makeSnapshotTo(destinationPath)` function.
+
 ##### Common test fixes
 
 Test infrastructure adds following common fixes to all test projects:

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/testbase/pathHelpers.kt

@@ -5,10 +5,13 @@
 
 package org.jetbrains.kotlin.gradle.testbase
 
+import java.io.IOException
+import java.nio.file.FileVisitResult
 import java.nio.file.Files
 import java.nio.file.Path
-import kotlin.io.path.extension
-import kotlin.io.path.relativeTo import kotlin.io.path.isRegularFile
+import java.nio.file.SimpleFileVisitor
+import java.nio.file.attribute.BasicFileAttributes
+import kotlin.io.path.*
 import kotlin.streams.asSequence
 import kotlin.streams.toList
 
@@ -64,4 +67,44 @@ internal fun Iterable<Path>.relativizeTo(basePath: Path): Iterable<Path> = map {
     it.relativeTo(basePath)
 }
 
-internal fun String.normalizePath() = replace("\\", "/")
+internal fun String.normalizePath() = replace("\\", "/")
+
+internal fun Path.copyRecursively(dest: Path) {
+    Files.walkFileTree(this, object : SimpleFileVisitor<Path>() {
+        override fun preVisitDirectory(
+            dir: Path,
+            attrs: BasicFileAttributes
+        ): FileVisitResult {
+            dest.resolve(relativize(dir)).createDirectories()
+            return FileVisitResult.CONTINUE
+        }
+
+        override fun visitFile(
+            file: Path,
+            attrs: BasicFileAttributes
+        ): FileVisitResult {
+            file.copyTo(dest.resolve(relativize(file)))
+            return FileVisitResult.CONTINUE
+        }
+    })
+}
+
+internal fun Path.deleteRecursively() {
+    Files.walkFileTree(this, object : SimpleFileVisitor<Path>() {
+        override fun visitFile(
+            file: Path,
+            fileAttributes: BasicFileAttributes
+        ): FileVisitResult {
+            file.deleteIfExists()
+            return FileVisitResult.CONTINUE
+        }
+
+        override fun postVisitDirectory(
+            dir: Path,
+            exception: IOException?
+        ): FileVisitResult {
+            dir.deleteIfExists()
+            return FileVisitResult.CONTINUE
+        }
+    })
+}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/testbase/testDsl.kt

@@ -12,9 +12,6 @@ import org.jetbrains.kotlin.gradle.BaseGradleIT.Companion.acceptAndroidSdkLicens
 import org.jetbrains.kotlin.test.util.KtTestUtil
 import java.io.File
 import java.nio.file.*
-import java.nio.file.Files.copy
-import java.nio.file.Files.createDirectories
-import java.nio.file.attribute.BasicFileAttributes
 import kotlin.io.path.*
 import kotlin.test.assertTrue
 
@@ -474,23 +471,3 @@ private fun Path.addHeapDumpOptions() {
         }
     }
 }
-
-private fun Path.copyRecursively(dest: Path) {
-    Files.walkFileTree(this, object : SimpleFileVisitor<Path>() {
-        override fun preVisitDirectory(
-            dir: Path,
-            attrs: BasicFileAttributes
-        ): FileVisitResult {
-            createDirectories(dest.resolve(relativize(dir)))
-            return FileVisitResult.CONTINUE
-        }
-
-        override fun visitFile(
-            file: Path,
-            attrs: BasicFileAttributes
-        ): FileVisitResult {
-            copy(file, dest.resolve(relativize(file)))
-            return FileVisitResult.CONTINUE
-        }
-    })
-}

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/testbase/testHelpers.kt

@@ -0,0 +1,81 @@
+/*
+ * 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.gradle.testbase
+
+import java.nio.file.Paths
+import java.nio.file.attribute.PosixFilePermission
+import kotlin.io.path.*
+
+/**
+ * Makes a snapshot of the current state of [TestProject] into [destinationPath].
+ *
+ * Method copies all files into `destinationPath/testProjectName/GradleVersion` directory
+ * and setup buildable project.
+ *
+ * To run task with the same build option as test - use `run.sh` (or `run.bat`) script.
+ */
+fun TestProject.makeSnapshotTo(destinationPath: String) {
+    val dest = Paths
+        .get(destinationPath)
+        .resolve(projectName)
+        .resolve(gradleVersion.version)
+        .also {
+            if (it.exists()) it.deleteRecursively()
+            it.createDirectories()
+        }
+
+    projectPath.copyRecursively(dest)
+    dest.resolve("gradle.properties").append(
+        """
+            kotlin_version=${buildOptions.kotlinVersion}
+            test_fixes_version=${TestVersions.Kotlin.CURRENT}
+            """.trimIndent()
+    )
+
+    dest.resolve("run.sh").run {
+        writeText(
+            """
+                #!/usr/bin/env sh
+                ./gradlew ${buildOptions.toArguments(gradleVersion).joinToString(separator = " ")} ${'$'}@ 
+                """.trimIndent()
+        )
+
+        setPosixFilePermissions(
+            setOf(
+                PosixFilePermission.OWNER_EXECUTE,
+                PosixFilePermission.OWNER_READ,
+                PosixFilePermission.OWNER_WRITE,
+            )
+        )
+    }
+
+    dest.resolve("run.bat").run {
+        writeText(
+            """
+                @rem Executing Gradle build
+                gradlew.bat ${buildOptions.toArguments(gradleVersion).joinToString(separator = " ")} %* 
+                """.trimIndent()
+        )
+    }
+
+    val wrapperDir = dest.resolve("gradle").resolve("wrapper").apply { createDirectories() }
+    wrapperDir.resolve("gradle-wrapper.properties").writeText(
+        """
+            distributionUrl=https\://services.gradle.org/distributions/gradle-${gradleVersion.version}-bin.zip
+            """.trimIndent()
+    )
+    // Copied from 'Wrapper' task class implementation
+    val projectRoot = Paths.get("../../../")
+    projectRoot.resolve("gradle").resolve("wrapper").resolve("gradle-wrapper.jar").run {
+        copyTo(wrapperDir.resolve(fileName))
+    }
+    projectRoot.resolve("gradlew").run {
+        copyTo(dest.resolve(fileName))
+    }
+    projectRoot.resolve("gradlew.bat").run {
+        copyTo(dest.resolve(fileName))
+    }
+}