Addressed comments from review https://codereview.chromium.org/226263007

pkg/shelf/test/request_test.dart

 // Copyright (c) 2014, 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 shelf.request_test;
 
 import 'dart:async';
 
 import 'package:shelf/shelf.dart';
 import 'package:unittest/unittest.dart';
 
 import 'test_util.dart';
 
-Request _request([Map<String, String> headers, Stream<List<int>> body]) {
-  return new Request("GET", LOCALHOST_URI, headers: headers, body: body);
+Request _request([Map<String, String> headers, Stream<List<int>> body,
+                  Map<String, Object> context]) {
+  return new Request("GET", LOCALHOST_URI, headers: headers, body: body,
+      context: context);
 }
 
 void main() {
   group('constructor', () {
     test('protocolVersion defaults to "1.1"', () {
       var request = new Request('GET', LOCALHOST_URI);
       expect(request.protocolVersion, '1.1');
     });
 
     test('provide non-default protocolVersion', () {
@@ skipping 145 matching lines @@
       ])));
 
       controller.add([104, 101, 108, 108, 111, 44]);
       return new Future(() {
         controller
           ..add([32, 119, 111, 114, 108, 100])
           ..close();
       });
     });
   });
+
+  group("context", () {
+    test("is correctly populated", () {
+      expect(_request({
+          'content-type': 'text/plain'
+      }, null, {
+          'my-param' : 42
+      }).context['my-param'], equals(42));
+    });
+  });
 }