Add additional file assertions.

File does not exist, file exists in the tree, file does not exist in
the tree.

^KT-45745 In Progress

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/Kotlin2JsGradlePluginIT.kt

@@ -77,7 +77,7 @@ class Kotlin2JsIrGradlePluginIT : AbstractKotlin2JsGradlePluginIT(true) {
             )
 
             build("build") {
-                assertFileNotExists("build/js/packages/kotlin-js-nodejs/kotlin/")
+                assertFileInProjectNotExists("build/js/packages/kotlin-js-nodejs/kotlin/")
             }
         }
     }

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

@@ -89,7 +89,7 @@ class SimpleKotlinGradleIT : KGPBaseTest() {
         project("moduleName", gradleVersion) {
             build("build") {
                 assertFileInProjectExists("build/classes/kotlin/main/META-INF/FLAG.kotlin_module")
-                assertFileNotExists("build/classes/kotlin/main/META-INF/moduleName.kotlin_module")
+                assertFileInProjectNotExists("build/classes/kotlin/main/META-INF/moduleName.kotlin_module")
                 assertOutputDoesNotContain("Argument -module-name is passed multiple times")
             }
         }
@@ -128,7 +128,7 @@ class SimpleKotlinGradleIT : KGPBaseTest() {
 
             build("build") {
                 assertDirectoryInProjectExists("$customBuildDirName/classes")
-                assertFileNotExists("build")
+                assertFileInProjectNotExists("build")
             }
         }
     }

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

@@ -36,18 +36,61 @@ fun GradleProject.assertFileInProjectExists(
     assertFileExists(projectPath.resolve(pathToFile))
 }
 
+fun GradleProject.assertFileExistsInTree(
+    pathToTreeRoot: Path,
+    fileName: String
+) {
+    val foundFile = pathToTreeRoot
+        .toFile()
+        .walk()
+        .find {
+            it.isFile && it.name == fileName
+        }
+
+    assert(foundFile != null) {
+        "File $fileName does not exists in $pathToTreeRoot!"
+    }
+}
 /**
  * Asserts file under [pathToFile] relative to the test project does not exist.
  */
-fun GradleProject.assertFileNotExists(
+fun GradleProject.assertFileInProjectNotExists(
     pathToFile: String
 ) {
-    val filePath = projectPath.resolve(pathToFile)
-    assert(!Files.exists(filePath)) {
-        "File '${filePath}' exists!"
+    assertFileNotExists(projectPath.resolve(pathToFile))
+}
+
+fun GradleProject.assertFileNotExists(
+    pathToFile: Path
+) {
+    assert(!Files.exists(pathToFile)) {
+        "File '${pathToFile}' exists!"
     }
 }
 
+fun GradleProject.assertFileNotExistsInTree(
+    pathToTreeRoot: Path,
+    fileName: String
+) {
+    val foundFile = pathToTreeRoot
+        .toFile()
+        .walk()
+        .find {
+            it.isFile && it.name == fileName
+        }
+
+    assert(foundFile == null) {
+        "File exists: ${foundFile!!.absolutePath}"
+    }
+}
+
+fun GradleProject.assertFileNotExistsInTree(
+    pathToTreeRoot: String,
+    fileName: String
+) {
+    assertFileNotExistsInTree(projectPath.resolve(pathToTreeRoot), fileName)
+}
+
 /**
  * Asserts directory under [pathToDir] relative to the test project exists and is a directory.
  */