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

pkg/shelf/test/response_test.dart

Index: pkg/shelf/test/response_test.dart
diff --git a/pkg/shelf/test/response_test.dart b/pkg/shelf/test/response_test.dart
index 9ee47c5f93360f8a62b82680a7bdd597ff12be3e..e1e3ae6f1078ef5b4b770da717f7847e5f0b263f 100644
--- a/pkg/shelf/test/response_test.dart
+++ b/pkg/shelf/test/response_test.dart
@@ -157,4 +157,54 @@ void main() {
       }).lastModified, equals(DateTime.parse("1994-11-06 08:49:37z")));
     });
   });
+
+  group("context", () {
+    test("are correctly populated in ok", () {
+      expect(new Response.ok("okay!", headers: {}, context: {
+          'my-param' : 42
+      }).context['my-param'], equals(42));
+    });
+
+    test("is correctly populated in forbidden", () {
+      expect(new Response.forbidden("okay!", headers: {}, context: {
+          'my-param' : 42
+      }).context['my-param'], equals(42));
+    });
+
+    test("is correctly populated in found", () {
+      expect(new Response.found("okay!", headers: {}, context: {
+          'my-param' : 42
+      }).context['my-param'], equals(42));
+    });
+
+    test("is correctly populated in internalServerError", () {
+      expect(new Response.internalServerError(headers: {}, context: {
+          'my-param' : 42
+      }).context['my-param'], equals(42));
+    });
+
+    test("is correctly populated in movedPermanently", () {
+      expect(new Response.movedPermanently("okay!", headers: {}, context: {
+          'my-param' : 42
+      }).context['my-param'], equals(42));
+    });
+
+    test("is correctly populated in notFound", () {
+      expect(new Response.notFound("okay!", headers: {}, context: {
+          'my-param' : 42
+      }).context['my-param'], equals(42));
+    });
+
+    test("is correctly populated in notModified", () {
+      expect(new Response.notModified(headers: {}, context: {
+          'my-param' : 42
+      }).context['my-param'], equals(42));
+    });
+
+    test("is correctly populated in seeOther", () {
+      expect(new Response.seeOther("other", headers: {}, context: {
+          'my-param' : 42
+      }).context['my-param'], equals(42));
+    });
+  });
 }