pkg/matcher: add isNaN and isNotNaN matchers

pkg/matcher/test/core_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 matcher.core_matchers_test;
 
 import 'package:matcher/matcher.dart';
 import 'package:unittest/unittest.dart' show test, group;
 
 import 'test_utils.dart';
@@ skipping 15 matching lines @@
   test('isNull', () {
     shouldPass(null, isNull);
     shouldFail(false, isNull, "Expected: null Actual: <false>");
   });
 
   test('isNotNull', () {
     shouldPass(false, isNotNull);
     shouldFail(null, isNotNull, "Expected: not null Actual: <null>");
   });
 
+  test('isNaN', () {
+    shouldPass(double.NAN, isNaN);
+    shouldFail(3.1, isNaN, "Expected: NaN Actual: <3.1>");
+  });
+
+  test('isNotNaN', () {
+    shouldPass(3.1, isNotNaN);
+    shouldFail(double.NAN, isNotNaN, "Expected: not NaN Actual: <NaN>");
+  });
+
   test('same', () {
     var a = new Map();
     var b = new Map();
     shouldPass(a, same(a));
     shouldFail(b, same(a), "Expected: same instance as {} Actual: {}");
   });
 
   test('equals', () {
     var a = new Map();
     var b = new Map();
@@ skipping 174 matching lines @@
   });
 }
 
 class _Bicycle {
   static final foo = bar();
 
   static bar() {
     return foo + 1;
   }
 }