Add corelib tests

test/codegen/corelib/double_round_to_double2_test.dart

Index: test/codegen/corelib/double_round_to_double2_test.dart
diff --git a/test/codegen/corelib/double_round_to_double2_test.dart b/test/codegen/corelib/double_round_to_double2_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..e2ed44ad61c50ea5ea6b5da08cfc81cb0fbaa55b
--- /dev/null
+++ b/test/codegen/corelib/double_round_to_double2_test.dart
@@ -0,0 +1,13 @@
+// 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.
+
+import 'package:expect/expect.dart';
+
+main() {
+  Expect.equals(0.0, 0.49999999999999994.roundToDouble());
+  Expect.equals(0.0, (-0.49999999999999994).roundToDouble());
+  Expect.isTrue(0.49999999999999994.roundToDouble() is double);
+  Expect.isTrue((-0.49999999999999994).roundToDouble().isNegative);
+  Expect.isTrue((-0.49999999999999994).roundToDouble() is double);
+}