Fix the tests.

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 470 matching lines @@
 ///
 /// This works because an actual pub executable that imports this will always
 /// start with "pub".
 final bool runningAsTest =
     !path.url.basename(Platform.script.path).startsWith('pub.');
 
 // TODO(nweiz): Use the test API when test#48 is fixed.
 /// Whether the current process is one of pub's test files being run through the
 /// test package's test runner.
 ///
-/// The test runner starts all tests from an entrypoint called
-/// "runInIsolate.dart'>
-final bool runningAsTestRunner =
-    path.url.basename(Platform.script.path).startsWith('runInIsolate.dart');
+/// The test runner starts all tests from a `data:` URI.
+final bool runningAsTestRunner = Platform.script.scheme == 'data';
 
 /// Whether the current process is a pub subprocess being run from a test.
 ///
 /// The "_PUB_TESTING" variable is automatically set for all the test code's
 /// invocations of pub.
 final bool runningFromTest = Platform.environment.containsKey('_PUB_TESTING');
 
 /// Whether pub is running from within the Dart SDK, as opposed to from the Dart
 /// source repository.
 final bool runningFromSdk =
@@ skipping 558 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;
 }