Unit test improvements:

pkg/unittest/lib/src/core_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;
 
 /**
  * Returns a matcher that matches empty strings, maps or iterables
  * (including collections).
  */
@@ skipping 154 matching lines @@
                 reason = _recursiveMatch(expected[key], actual[key],
                     'with key <${key}> ${location}', depth+1);
                 if (reason != null) {
                   break;
                 }
               }
             }
           }
         }
       } else {
+        reason = new StringDescription();
+        var includeTypes = expected.runtimeType != actual.runtimeType;
         // If we have recursed, show the expected value too; if not,
-        // expect() will show it for us.
-        reason = new StringDescription();
-        if (depth > 1) {
-          reason.add('expected ').addDescriptionOf(expected).add(' but was ').
-              addDescriptionOf(actual);
-        } else {
-          reason.add('was ').addDescriptionOf(actual);
+        // expect() will show it for us. As expect will not show type
+        // mismatches at the top level we handle those here too.
+        if (includeTypes || depth > 1) {
+          reason.add('expected ');
+          if (includeTypes) {
+            reason..add(expected.runtimeType).add(':');
+          }
+          reason.addDescriptionOf(expected).add(' but ');
         }
+        reason.add('was ');
+        if (includeTypes) {
+          reason..add(actual.runtimeType).add(':');
+        }
+        reason.addDescriptionOf(actual);
       }
     }
     if (reason != null && location.length > 0) {
       reason.add(' ').add(location);
     }
     return reason;
   }
 
   String _match(expected, actual) {
     Description reason = _recursiveMatch(expected, actual, '', 0);
@@ skipping 119 matching lines @@
             var stackTrace = e.stackTrace.toString();
             stackTrace = "  ${stackTrace.replaceAll("\n", "\n  ")}";
             reason = "Actual exception trace:\n$stackTrace";
           }
           expect(e.error, _matcher, reason: reason);
         });
       });
 
       // It hasn't failed yet.
       return true;
+    } else if (item is! Function) {

[Siggi Cherem (dart-lang), 2013/02/12 21:07:09]

btw seems that the fix didn't make it to this patch.

+      return false;
     }
 
     try {
       item();
       return false;
     } catch (e, s) {
       if (_matcher == null ||_matcher.matches(e, matchState)) {
         return true;
       } else {
         matchState.state = {
@@ skipping 10 matching lines @@
       return description.add("throws an exception");
     } else {
       return description.add('throws an exception which matches ').
           addDescriptionOf(_matcher);
     }
   }
 
   Description describeMismatch(item, Description mismatchDescription,
                                MatchState matchState,
                                bool verbose) {
-    if (_matcher == null ||  matchState.state == null) {
+    if (item is! Function && item is! Future) {
+      return mismatchDescription.add(' not a Function or Future');
+    } else if (_matcher == null ||  matchState.state == null) {
       return mismatchDescription.add(' no exception');
     } else {
       mismatchDescription.
           add(' exception ').addDescriptionOf(matchState.state['exception']);
       if (verbose) {
           mismatchDescription.add(' at ').
           add(matchState.state['stack'].toString());
       }
        mismatchDescription.add(' does not match ').addDescriptionOf(_matcher);
        return mismatchDescription;
@@ skipping 348 matching lines @@
       description.add(_featureDescription).add(' ').addDescriptionOf(_matcher);
 
   Description describeMismatch(item, Description mismatchDescription,
                                MatchState matchState, bool verbose) {
     mismatchDescription.add(_featureName).add(' ');
     _matcher.describeMismatch(matchState.state['feature'], mismatchDescription,
         matchState.state['innerState'], verbose);
     return mismatchDescription;
   }
 }