Add mirrors tests

test/codegen/lib/mirrors/library_uri_package_test.dart

+// Copyright (c) 2011, 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.
+
+// Test library uri for a library read as a package .
+
+library MirrorsTest;
+
+import 'dart:mirrors';
+import 'package:args/args.dart';
+import 'package:unittest/unittest.dart';
+
+testLibraryUri(var value, Uri expectedUri) {
+  var valueMirror = reflect(value);
+  ClassMirror valueClass = valueMirror.type;
+  LibraryMirror valueLibrary = valueClass.owner;
+  Uri uri = valueLibrary.uri;
+  if (uri.scheme != "https" ||
+      uri.host != "dartlang.org" ||
+      uri.path != "/dart2js-stripped-uri") {
+    expect(uri, equals(expectedUri));
+  }
+}
+
+main() {
+  var mirrors = currentMirrorSystem();
+  test("Test package library uri", () {
+    testLibraryUri(new ArgParser(),
+        Uri.parse('package:args/src/arg_parser.dart'));
+  });
+}