First stab at "pub run" command.

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

Index: sdk/lib/_internal/pub/test/run/runs_transformer_in_entrypoint_test.dart
diff --git a/sdk/lib/_internal/pub/test/serve/does_not_crash_if_an_unused_dart_file_has_a_syntax_error_test.dart b/sdk/lib/_internal/pub/test/run/runs_transformer_in_entrypoint_test.dart
similarity index 57%
copy from sdk/lib/_internal/pub/test/serve/does_not_crash_if_an_unused_dart_file_has_a_syntax_error_test.dart
copy to sdk/lib/_internal/pub/test/run/runs_transformer_in_entrypoint_test.dart
index 09d41bd9347bbd7102deebb68df7c86cbccf84b4..d777d61a81fcbcd31710f15ca54103498cafdc15 100644
--- a/sdk/lib/_internal/pub/test/serve/does_not_crash_if_an_unused_dart_file_has_a_syntax_error_test.dart
+++ b/sdk/lib/_internal/pub/test/run/runs_transformer_in_entrypoint_test.dart
@@ -1,36 +1,43 @@
-// 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.
 
-library pub_tests;
-
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
+import '../serve/utils.dart';
 import 'utils.dart';
 
+const SCRIPT = """
+const TOKEN = "hi";
+main() {
+  print(TOKEN);
+}
+""";
+
 main() {
   initConfig();
   withBarbackVersions("any", () {
-    integration("doesn't crash if an unused .dart file has a syntax error", () {
+    integration('runs transformers in the entrypoint package', () {
       d.dir(appPath, [
         d.pubspec({
           "name": "myapp",
           "transformers": ["myapp/src/transformer"]
         }),
         d.dir("lib", [d.dir("src", [
-          d.file("transformer.dart", REWRITE_TRANSFORMER),
-          d.file("unused.dart", "(*&^#@")
+          d.file("transformer.dart", dartTransformer("transformed"))
         ])]),
-        d.dir("web", [
-          d.file("foo.txt", "foo")
+        d.dir("bin", [
+          d.file("hi.dart", SCRIPT)
         ])
       ]).create();
 
       createLockFile('myapp', pkg: ['barback']);
 
-      var server = pubServe();
-      requestShouldSucceed("foo.out", "foo.out");
-      endPubServe();
+      var pub = pubRun(args: ["hi"],
+          transformers: ["myapp/src/transformer"]);
+
+      pub.stdout.expect("(hi, transformed)");
+      pub.shouldExit();
     });
   });
 }