Add File.copy(Sync) to dart:io.

tests/standalone/io/file_copy_test.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+//
+// Dart test program for testing File.copy*
+
+import 'dart:io';
+
+import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
+
+const FILE_CONTENT1 = 'some string';
+const FILE_CONTENT2 = 'some other string';
+
+void testCopySync() {
+  var tmp = Directory.systemTemp.createTempSync('dart-file-copy');
+
+  var file1 = new File('${tmp.path}/file1');
+  file1.writeAsStringSync(FILE_CONTENT1);
+  Expect.equals(FILE_CONTENT1, file1.readAsStringSync());
+
+  // Copy to new file works.
+  var file2 = file1.copySync('${tmp.path}/file2');
+  Expect.equals(FILE_CONTENT1, file1.readAsStringSync());
+  Expect.equals(FILE_CONTENT1, file2.readAsStringSync());
+
+  // Override works for files.
+  file2.writeAsStringSync(FILE_CONTENT2);
+  file2.copySync(file1.path);
+  Expect.equals(FILE_CONTENT2, file1.readAsStringSync());
+  Expect.equals(FILE_CONTENT2, file2.readAsStringSync());
+
+  // Fail when coping to directory.
+  var dir = new Directory('${tmp.path}/dir')..createSync();
+  Expect.throws(() => file1.copySync(dir.path));
+  Expect.equals(FILE_CONTENT2, file1.readAsStringSync());
+
+  tmp.deleteSync(recursive: true);
+}
+
+
+void testCopy() {
+  asyncStart();
+  var tmp = Directory.systemTemp.createTempSync('dart-file-copy');
+
+  var file1 = new File('${tmp.path}/file1');
+  file1.writeAsStringSync(FILE_CONTENT1);
+  Expect.equals(FILE_CONTENT1, file1.readAsStringSync());
+
+  // Copy to new file works.
+  file1.copy('${tmp.path}/file2')
+    .then((file2) {
+      Expect.equals(FILE_CONTENT1, file1.readAsStringSync());
+      Expect.equals(FILE_CONTENT1, file2.readAsStringSync());
+
+      // Override works for files.
+      file2.writeAsStringSync(FILE_CONTENT2);
+      return file2.copy(file1.path)
+        .then((_) {
+          Expect.equals(FILE_CONTENT2, file1.readAsStringSync());
+          Expect.equals(FILE_CONTENT2, file2.readAsStringSync());
+
+          // Fail when coping to directory.
+          var dir = new Directory('${tmp.path}/dir')..createSync();
+
+          return file1.copy(dir.path)
+            .then((_) => Expect.fail('expected error'),
+                  onError: (_) {})
+            .then((_) {
+              Expect.equals(FILE_CONTENT2, file1.readAsStringSync());
+            });
+
+        });
+    })
+    .whenComplete(() {
+      tmp.deleteSync(recursive: true);
+      asyncEnd();
+    });
+
+}
+
+
+main() {
+  testCopySync();
+  testCopy();
+}