Handle parsing the "version" file better.

utils/tests/pub/test_pub.dart

 // Copyright (c) 2012, 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.
 
 /// Test infrastructure for testing pub. Unlike typical unit tests, most pub
 /// tests are integration tests that stage some stuff on the file system, run
 /// pub, and then validate the results. This library provides an API to build
 /// tests like that.
 library test_pub;
 
@@ skipping 790 matching lines @@
   }
 
   /// Validates that at least one file in [dir] matching [name] is valid
   /// according to [validate]. [validate] should complete to an exception if
   /// the input path is invalid.
   Future _validateOneMatch(String dir, Future validate(String path)) {
     // Special-case strings to support multi-level names like "myapp/packages".
     if (name is String) {
       var path = join(dir, name);
       return exists(path).then((exists) {
-        if (!exists) Expect.fail('File $name in $dir not found.');
+        if (!exists) {
+          throw new ExpectException('File $name in $dir not found.');
+        }
         return validate(path);
       });
     }
 
     // TODO(nweiz): remove this when issue 4061 is fixed.
     var stackTrace;
     try {
       throw "";
     } catch (_, localStackTrace) {
       stackTrace = localStackTrace;
     }
 
     return listDir(dir).then((files) {
       var matches = files.where((file) => endsWithPattern(file, name)).toList();
       if (matches.isEmpty) {
-        Expect.fail('No files in $dir match pattern $name.');
+        throw new ExpectException('No files in $dir match pattern $name.');
       }
       if (matches.length == 1) return validate(matches[0]);
 
       var failures = [];
       var successes = 0;
       var completer = new Completer();
       checkComplete() {
         if (failures.length + successes != matches.length) return;
         if (successes > 0) {
           completer.complete();
@@ skipping 43 matching lines @@
   Future delete(dir) {
     return deleteFile(join(dir, _stringName));
   }
 
   /// Validates that this file correctly matches the actual file at [path].
   Future validate(String path) {
     return _validateOneMatch(path, (file) {
       return readTextFile(file).then((text) {
         if (text == contents) return null;
 
-        Expect.fail('File $file should contain:\n\n$contents\n\n'
-                    'but contained:\n\n$text');
+        throw new ExpectException(
+            'File $file should contain:\n\n$contents\n\n'
+            'but contained:\n\n$text');
       });
     });
   }
 
   /// Loads the contents of the file.
   InputStream load(List<String> path) {
     if (!path.isEmpty) {
       var joinedPath = Strings.join(path, '/');
       throw "Can't load $joinedPath from within $name: not a directory.";
     }
@@ skipping 223 matching lines @@
 
 /// A descriptor that validates that no file exists with the given name.
 class NothingDescriptor extends Descriptor {
   NothingDescriptor(String name) : super(name);
 
   Future create(dir) => new Future.immediate(null);
   Future delete(dir) => new Future.immediate(null);
 
   Future validate(String dir) {
     return exists(join(dir, name)).then((exists) {
-      if (exists) Expect.fail('File $name in $dir should not exist.');
+      if (exists) {
+        throw new ExpectException('File $name in $dir should not exist.');
+      }
     });
   }
 
   InputStream load(List<String> path) {
     if (path.isEmpty) {
       throw "Can't load the contents of $name: it doesn't exist.";
     } else {
       throw "Can't load ${Strings.join(path, '/')} from within $name: $name "
         "doesn't exist.";
     }
@@ skipping 399 matching lines @@
 /// calling [completion] is unnecessary.
 void expectLater(Future actual, matcher, {String reason,
     FailureHandler failureHandler, bool verbose: false}) {
   _schedule((_) {
     return actual.then((value) {
       expect(value, matcher, reason: reason, failureHandler: failureHandler,
           verbose: false);
     });
   });
 }