Some unit test fixes

tests/lib/unittest/test_utils.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.
+
+int errorCount;
+String errorString;
+var _testHandler = null;
+
+class MyFailureHandler extends DefaultFailureHandler {
+  void fail(String reason) {
+    ++errorCount;
+    errorString = reason;
+  }
+}
+
+void initUtils() {
+  if (_testHandler == null) {
+    _testHandler = new MyFailureHandler();
+  }
+}
+
+void shouldFail(value, Matcher matcher, expected) {
+  configureExpectHandler(_testHandler);
+  errorCount = 0;
+  errorString = '';
+  expect(value, matcher);
+  configureExpectHandler(null);
+  expect(errorCount, equals(1));
+  if (expected is String) {
+    expect(errorString, equalsIgnoringWhitespace(expected));
+  } else {
+   expect(errorString, expected);
+  }
+}
+
+void shouldPass(value, Matcher matcher) {
+  configureExpectHandler(_testHandler);
+  errorCount = 0;
+  errorString = '';
+  expect(value, matcher);
+  configureExpectHandler(null);
+  expect(errorCount, equals(0));
+}
+