Improved error messages from unittest.

pkg/unittest/lib/src/operator_matchers.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.
 
 part of matcher;
 
 /**
  * This returns a matcher that inverts [matcher] to its logical negation.
  */
 Matcher isNot(matcher) => new _IsNot(wrapMatcher(matcher));
 
 class _IsNot extends BaseMatcher {
   final Matcher _matcher;
 
   const _IsNot(Matcher this._matcher);
 
-  bool matches(item, MatchState matchState) =>
+  bool matches(item, Map matchState) =>
       !_matcher.matches(item, matchState);
 
   Description describe(Description description) =>
     description.add('not ').addDescriptionOf(_matcher);
 }
 
 /**
  * This returns a matcher that matches if all of the matchers passed as
  * arguments (up to 7) match. Instead of passing the matchers separately
  * they can be passed as a single List argument.
@@ skipping 43 matching lines @@
     }
     return new _AllOf(matchers);
   }
 }
 
 class _AllOf extends BaseMatcher {
   final Iterable<Matcher> _matchers;
 
   const _AllOf(this._matchers);
 
-  bool matches(item, MatchState matchState) {
+  bool matches(item, Map matchState) {
      for (var matcher in _matchers) {
        if (!matcher.matches(item, matchState)) {
-         matchState.state = {
-             'matcher': matcher,
-             'state': matchState.state
-         };
+        addStateInfo(matchState, {'matcher': matcher});
          return false;
        }
      }
      return true;
   }
 
   Description describeMismatch(item, Description mismatchDescription,
-                               MatchState matchState, bool verbose) {
-    var matcher = matchState.state['matcher'];
+                               Map matchState, bool verbose) {
+    var matcher = matchState['matcher'];
     matcher.describeMismatch(item, mismatchDescription,
-        matchState.state['state'], verbose);
-    mismatchDescription.add(" (wasn't ").addDescriptionOf(matcher).add(')');
+        matchState['state'], verbose);
     return mismatchDescription;
   }
 
   Description describe(Description description) =>
       description.addAll('(', ' and ', ')', _matchers);
 }
 
 /**
  * Matches if any of the given matchers evaluate to true. The
  * arguments can be a set of matchers as separate parameters
@@ skipping 49 matching lines @@
     }
     return new _AnyOf(matchers);
   }
 }
 
 class _AnyOf extends BaseMatcher {
   final Iterable<Matcher> _matchers;
 
   const _AnyOf(this._matchers);
 
-  bool matches(item, MatchState matchState) {
+  bool matches(item, Map matchState) {
      for (var matcher in _matchers) {
        if (matcher.matches(item, matchState)) {
          return true;
        }
      }
      return false;
   }
 
   Description describe(Description description) =>
     description.addAll('(', ' or ', ')', _matchers);
 }