First stab at "pub run" command.

sdk/lib/_internal/pub/test/run/runs_the_script_in_checked_mode_test.dart

Index: sdk/lib/_internal/pub/test/run/runs_the_script_in_checked_mode_test.dart
diff --git a/sdk/lib/_internal/pub/test/barback/fails_if_dir_arg_does_not_exist_test.dart b/sdk/lib/_internal/pub/test/run/runs_the_script_in_checked_mode_test.dart
similarity index 53%
copy from sdk/lib/_internal/pub/test/barback/fails_if_dir_arg_does_not_exist_test.dart
copy to sdk/lib/_internal/pub/test/run/runs_the_script_in_checked_mode_test.dart
index 2f5d56e9ac1427f4d7d620c90903c1bb625f42a9..fd6b27af9c707a69623fa08f72982d0ecb4f3492 100644
--- a/sdk/lib/_internal/pub/test/barback/fails_if_dir_arg_does_not_exist_test.dart
+++ b/sdk/lib/_internal/pub/test/run/runs_the_script_in_checked_mode_test.dart
@@ -1,28 +1,30 @@
-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS d.file
+// Copyright (c) 2014, 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:scheduled_test/scheduled_test.dart';
 
-import '../../lib/src/exit_codes.dart' as exit_codes;
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
-import 'utils.dart';
 
+const SCRIPT = """
 main() {
-  initConfig();
+  int a = true;
+}
+""";
 
-  setUp(() {
+main() {
+  initConfig();
+  integration('runs the script in checked mode by default', () {
     d.dir(appPath, [
       d.appPubspec(),
-      d.dir("bar", [
-        d.file("file.txt", "contents")
+      d.dir("bin", [
+        d.file("script.dart", SCRIPT)
       ])
     ]).create();
-  });
 
-  pubBuildAndServeShouldFail("if a specified directory doesn't exist",
-      args: ["foo", "bar", "baz"],
-      error: 'Directories "foo" and "baz" do not exist.',
-      exitCode: exit_codes.DATA);
+    schedulePub(args: ["run", "script"],
+        error: contains("'bool' is not a subtype of type 'int' of 'a'"),
+        exitCode: 255);
+  });
 }