Clean warnings and refactor stdlib tests.

Merge RangeJVMTest into RangeTest.

libraries/stdlib/test/io/FileTreeWalks.kt

@@ -229,10 +229,10 @@ class FileTreeWalkTest {
         val basedir = createTestFiles()
         try {
             var i = 0
-            basedir.walkTopDown().forEach { it -> i++ }
+            basedir.walkTopDown().forEach { _ -> i++ }
             assertEquals(10, i);
             i = 0
-            basedir.walkBottomUp().forEach { it -> i++ }
+            basedir.walkBottomUp().forEach { _ -> i++ }
             assertEquals(10, i);
         } finally {
             basedir.deleteRecursively()
@@ -282,7 +282,7 @@ class FileTreeWalkTest {
                 files.add(file.relativeToOrSelf(basedir))
             }
 
-            fun visitDirectoryFailed(dir: File, e: IOException) {
+            fun visitDirectoryFailed(dir: File, @Suppress("UNUSED_PARAMETER") e: IOException) {
                 assertEquals(stack.last(), dir)
                 //stack.removeAt(stack.lastIndex)
                 failed.add(dir.name)
@@ -405,7 +405,7 @@ class FileTreeWalkTest {
         try {
             File(basedir, "8/4.txt").createNewFile()
             var count = 0
-            basedir.walkTopDown().takeWhile { it -> count == 0 }.forEach {
+            basedir.walkTopDown().takeWhile { _ -> count == 0 }.forEach {
                 if (it.name == "4.txt") {
                     count++
                 }

libraries/stdlib/test/io/Files.kt

@@ -141,6 +141,7 @@ class FilesTest {
             assertEquals("", file.toRelativeString(file), "file should have empty path relative to itself: $file")
 
         for (file in files) {
+            @Suppress("NAME_SHADOWING")
             for (base in bases) {
                 val rootedFile = root.resolve(file)
                 val rootedBase = root.resolve(base)
@@ -158,7 +159,9 @@ class FilesTest {
 
         fun assertFailsRelativeTo(file: File, base: File) {
             val e = assertFailsWith<IllegalArgumentException>("file: $file, base: $base") { file.relativeTo(base) }
-//            println(e.message)
+            val message = assertNotNull(e.message)
+            assert(file.toString() in message)
+            assert(base.toString() in message)
         }
 
         val allFiles = listOf(absolute, relative) + if (isBackslashSeparator) listOf(networkShare1, networkShare2) else emptyList()
@@ -220,7 +223,7 @@ class FilesTest {
 
         if (isBackslashSeparator) {
             val diskRooted = File("""C:\foo\bar""")
-            assertTrue(rooted.isRooted)
+            assertTrue(diskRooted.isRooted)
 //            assertEquals("""C:\""", diskRooted.rootName)
 
             val networkRooted = File("""\\network\share\""")
@@ -516,7 +519,7 @@ class FilesTest {
 
             var conflicts = 0
             src.copyRecursively(dst) {
-                file: File, e: IOException ->
+                _: File, e: IOException ->
                 if (e is FileAlreadyExistsException) {
                     conflicts++
                     OnErrorAction.SKIP
@@ -531,7 +534,7 @@ class FilesTest {
                     dst.deleteRecursively()
                     var caught = false
                     assertTrue(src.copyRecursively(dst) {
-                        file: File, e: IOException ->
+                        _: File, e: IOException ->
                         if (e is AccessDeniedException) {
                             caught = true
                             OnErrorAction.SKIP
@@ -552,10 +555,7 @@ class FilesTest {
                 src.copyRecursively(dst)
             }
 
-            assertFalse(src.copyRecursively(dst) {
-                file: File, e: IOException ->
-                OnErrorAction.TERMINATE
-            })
+            assertFalse(src.copyRecursively(dst) { _, _ -> OnErrorAction.TERMINATE })
         } finally {
             src.deleteRecursively()
             dst.deleteRecursively()

libraries/stdlib/test/io/ReadWrite.kt

@@ -143,7 +143,7 @@ class ReadWriteTest {
     }
 
     @Test fun testPlatformNullUse() {
-        fun <T> platformNull() = java.util.Collections.singleton(null as T).first()
+        fun <T> platformNull() = @Suppress("UNCHECKED_CAST") java.util.Collections.singleton(null as T).first()
         val resource = platformNull<java.io.Closeable>()
         val result = resource.use {
             "ok"