pkg/matcher: upgrate tests to test

test/pretty_print_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 matcher.pretty_print_test;
 
 import 'dart:collection';
 
 import 'package:matcher/matcher.dart';
 import 'package:matcher/src/pretty_print.dart';
-import 'package:unittest/unittest.dart' show group, test, expect;
+import 'package:test/test.dart' show group, test, expect;
 
 class DefaultToString {}
 
 class CustomToString {
   String toString() => "string representation";
 }
 
 class _PrivateName {
   String toString() => "string representation";
 }
@@ skipping 206 matching lines @@
     test("that's not a list", () {
       expect(prettyPrint([1, 2, 3, 4].map((n) => n * 2)),
           equals("MappedListIterable:[2, 4, 6, 8]"));
     });
 
     test("that's not a list and has a private name", () {
       expect(prettyPrint(new _PrivateNameIterable()), equals("?:[1, 2, 3]"));
     });
   });
 }