Unit test improvements:

pkg/unittest/test/matchers_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 unittestTests;
 import 'package:unittest/unittest.dart';
 import 'dart:async';
 part 'test_utils.dart';
 
 doesNotThrow() {}
@@ skipping 110 matching lines @@
       shouldPass(0, anything);
       shouldPass(null, anything);
       shouldPass(a, anything);
       shouldFail(a, isNot(anything), "Expected: not anything but: was <{}>.");
     });
 
     test('throws', () {
       shouldFail(doesNotThrow, throws,
         "Expected: throws an exception but: no exception.");
       shouldPass(doesThrow, throws);
+      shouldFail(true, throws,
+          "Expected: throws an exception but: not a Function or Future.");
     });
 
     test('throwsA', () {
       shouldPass(doesThrow, throwsA(equals('X')));
       shouldFail(doesThrow, throwsA(equals('Y')),
         "Expected: throws an exception which matches 'Y' "
         "but:  exception 'X' does not match 'Y'.");
     });
 
     test('throwsFormatException', () {
@@ skipping 95 matching lines @@
       shouldFail(b, hasLength(2),
         "Expected: an object with length of <2> "
         "but: was <[0]> with length of <1>.");
 
       b.add(0);
       shouldFail(b, hasLength(1),
         "Expected: an object with length of <1> "
         "but: was <[0, 0]> with length of <2>.");
       shouldPass(b, hasLength(2));
     });
+
+    test('type mismatch', () {
+      var a = new DateTime.utc(2000);
+      var b = a.toString();
+      shouldFail(a, equals(b),
+          "Expected: '2000-01-01 00:00:00.000Z' "
+          "but: expected String:'2000-01-01 00:00:00.000Z' "
+          "but was DateTime:<2000-01-01 00:00:00.000Z>.");
+    });
   });
 
   group('Numeric Matchers', () {
 
     test('greaterThan', () {
       shouldPass(10, greaterThan(9));
       shouldFail(9, greaterThan(10),
         "Expected: a value greater than <10> but: was <9>.");
     });
 
@@ skipping 438 matching lines @@
       var w = new Widget();
       w.price = 10;
       shouldPass(w, new HasPrice(greaterThan(0)));
       shouldFail(w, new HasPrice(greaterThan(10)),
           'Expected: Widget with a price that is a value greater than <10> '
           'but: price was <10>.');
     });
   });
 }