A few more fixes for testing in the repo.

lib/src/io.dart

 // 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.
 
 /// Helper functionality to make working with IO easier.
 library pub.io;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:convert';
@@ skipping 478 matching lines @@
 final bool runningFromTest = Platform.script.path.endsWith('.test.snapshot');
 
 /// Whether pub is running from within the Dart SDK, as opposed to from the Dart
 /// source repository.
 final bool runningFromSdk =
     !runningFromTest && Platform.script.path.endsWith('.snapshot');
 
 /// A regular expression to match the script path of a pub script running from
 /// source in the Dart repo.
 final _dartRepoRegExp = new RegExp(
-    r"/third_party/pkg_tested/pub/(bin/pub.dart|test/.*_test\.dart)$");
+    r"/third_party/pkg_tested/pub/("
+            r"bin/pub\.dart"
+        r"|"
+            r"\.pub/pub\.test\.snapshot"
+        r"|"
+            r"test/.*_test\.dart"
+        r")$");
 
 /// Whether pub is running from source in the Dart repo.
 ///
 /// This can happen when building Observatory, for example.
 final bool runningFromDartRepo =
     Platform.script.path.contains(_dartRepoRegExp);
 
 /// Resolves [target] relative to the path to pub's `asset` directory.
 String assetPath(String target) => runningFromSdk
     ? sdkAssetPath(target)
@@ skipping 549 matching lines @@
 
   // TODO(rnystrom): Remove this and change to returning one string.
   static List<String> _toLines(String output) {
     var lines = splitLines(output);
     if (!lines.isEmpty && lines.last == "") lines.removeLast();
     return lines;
   }
 
   bool get success => exitCode == exit_codes.SUCCESS;
 }