Add Fasta tests.

pkg/fasta/test/casts.dart

Index: pkg/fasta/test/casts.dart
diff --git a/pkg/fasta/test/casts.dart b/pkg/fasta/test/casts.dart
new file mode 100644
index 0000000000000000000000000000000000000000..2c7a621088313b479bdc25f1049c1633353969b6
--- /dev/null
+++ b/pkg/fasta/test/casts.dart
@@ -0,0 +1,21 @@
+// Copyright (c) 2016, 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.
+
+main() {
+  print("" as String);
+  print(1 as int);
+  print(1.0 as double);
+
+  print("" is String);
+  print("" is int);
+  print("" is double);
+
+  print(1 is String);
+  print(1 is int);
+  print(1 is double);
+
+  print(1.0 is String);
+  print(1.0 is int);
+  print(1.0 is double);
+}