Improved the way we generate mismatch descriptions.

utils/tests/pub/version_test.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.
 
 #library('version_test');
 
 #import('../../../lib/unittest/unittest.dart');
 #import('../../pub/utils.dart');
 #import('../../pub/version.dart');
 
@@ skipping 366 matching lines @@
     });
   });
 }
 
 class VersionConstraintMatcher implements Matcher {
   final List<Version> _expected;
   final bool _allow;
 
   VersionConstraintMatcher(this._expected, this._allow);
 
-  bool matches(item) => (item is VersionConstraint) &&
+  bool matches(item, MatchState matchState) => (item is VersionConstraint) &&
       _expected.every((version) => item.allows(version) == _allow);
 
   Description describe(Description description) =>
       description.add(' ${_allow ? "allows" : "does not allow"} versions');
 
-  Description describeMismatch(item, Description mismatchDescription) {
+  Description describeMismatch(item, Description mismatchDescription,
+      MatchState matchState, bool verbose) {
     if (item is! VersionConstraint) {
       mismatchDescription.add('was not a VersionConstraint');
       return mismatchDescription;
     }
 
     bool first = true;
     for (var version in _expected) {
       if (item.allows(version) != _allow) {
         if (first) {
           if (_allow) {
@@ skipping 20 matching lines @@
 Matcher doesNotAllow(List<Version> versions) =>
     new VersionConstraintMatcher(versions, false);
 
 throwsIllegalArg(function) {
   expectThrow(function, (e) => e is IllegalArgumentException);
 }
 
 throwsBadFormat(function) {
   expectThrow(function, (e) => e is FormatException);
 }