Replace the existing unittest APIs with the new runner infrastructure.

test/returning_future_using_runasync_test.dart

-// Copyright (c) 2013, 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 unittest.returning_future_using_runasync_test;
-
-import 'dart:async';
-
-import 'package:metatest/metatest.dart';
-import 'package:unittest/unittest.dart';
-
-void main() => initTests(_test);
-
-void _test(message) {
-  initMetatest(message);
-
-  expectTestResults('test returning future using scheduleMicrotask', () {
-    test("successful", () {
-      return new Future.sync(() {
-        scheduleMicrotask(() {
-          expect(true, true);
-        });
-      });
-    });
-    test("fail1", () {
-      var callback = expectAsync(() {});
-      return new Future.sync(() {
-        scheduleMicrotask(() {
-          expect(true, false);
-          callback();
-        });
-      });
-    });
-    test('error1', () {
-      var callback = expectAsync(() {});
-      var excesscallback = expectAsync(() {});
-      return new Future.sync(() {
-        scheduleMicrotask(() {
-          excesscallback();
-          excesscallback();
-          callback();
-        });
-      });
-    });
-    test("fail2", () {
-      var callback = expectAsync(() {});
-      return new Future.sync(() {
-        scheduleMicrotask(() {
-          fail('failure');
-          callback();
-        });
-      });
-    });
-    test('error2', () {
-      var callback = expectAsync(() {});
-      var excesscallback = expectAsync(() {});
-      return new Future.sync(() {
-        scheduleMicrotask(() {
-          excesscallback();
-          excesscallback();
-          excesscallback();
-          callback();
-        });
-      });
-    });
-    test('foo6', () {});
-  }, [
-    {'description': 'successful', 'result': 'pass',},
-    {
-      'description': 'fail1',
-      'message': 'Expected: <false>\n' '  Actual: <true>\n' '',
-      'result': 'fail',
-    },
-    {
-      'description': 'error1',
-      'message': 'Callback called more times than expected (1).',
-      'result': 'fail',
-    },
-    {'description': 'fail2', 'message': 'failure', 'result': 'fail',},
-    {
-      'description': 'error2',
-      'message': 'Callback called more times than expected (1).',
-      'result': 'fail',
-    },
-    {'description': 'foo6', 'result': 'pass',}
-  ]);
-}