Improved error messages from unittest.

pkg/unittest/lib/mock.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.
 
 /**
  * A simple mocking/spy library.
  *
  * ## Installing ##
  *
  * Use [pub][] to install this package. Add the following to your `pubspec.yaml`
@@ skipping 270 matching lines @@
     }
     d.add(')');
     return d.toString();
   }
 
   /**
    * Given a [method] name and list of [arguments], return true
    * if it matches this [CallMatcher.
    */
   bool matches(String method, List arguments) {
-    var matchState = new MatchState();
+    var matchState = {};
     if (!nameFilter.matches(method, matchState)) {
       return false;
     }
     var numArgs = (arguments == null) ? 0 : arguments.length;
     if (numArgs < argMatchers.length) {
       throw new Exception("Less arguments than matchers for $method.");
     }
     for (var i = 0; i < argMatchers.length; i++) {
       if (!argMatchers[i].matches(arguments[i], matchState)) {
         return false;
@@ skipping 232 matching lines @@
                           Matcher actionMatcher,
                           bool destructive = false]) {
     if (mockNameFilter == null) {
       mockNameFilter = anything;
     } else {
       mockNameFilter = wrapMatcher(mockNameFilter);
     }
     Function entryFilter = _makePredicate(logFilter);
     String filterName = _qualifiedName(mockNameFilter, logFilter.toString());
     LogEntryList rtn = new LogEntryList(filterName);
-    MatchState matchState = new MatchState();
+    var matchState = {};
     for (var i = 0; i < logs.length; i++) {
       LogEntry entry = logs[i];
       if (mockNameFilter.matches(entry.mockName, matchState) &&
           entryFilter(entry)) {
         if (actionMatcher == null ||
             actionMatcher.matches(entry, matchState)) {
           rtn.add(entry);
           if (destructive) {
             int startIndex = i--;
             logs.removeRange(startIndex, startIndex + 1);
@@ skipping 989 matching lines @@
       }
     }
   }
 
   /** Clear both logs and behavior. */
   void reset() {
     resetBehavior();
     clearLogs();
   }
 }