Make MediaType case-insensitive, following the spec.

test/media_type_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 http_parser.media_type_test;
 
 import 'package:http_parser/http_parser.dart';
 import 'package:test/test.dart';
 
 void main() {
@@ skipping 52 matching lines @@
           throwsFormatException);
     });
 
     test("parses quoted parameters", () {
       var type = new MediaType.parse(
           'text/plain; foo="bar space"; baz="bang\\\\escape"');
       expect(type.mimeType, equals("text/plain"));
       expect(
           type.parameters, equals({"foo": "bar space", "baz": "bang\\escape"}));
     });
+
+    test("lower-cases type and subtype", () {
+      var type = new MediaType.parse('TeXt/pLaIn');
+      expect(type.type, equals("text"));
+      expect(type.subtype, equals("plain"));
+      expect(type.mimeType, equals("text/plain"));
+    });
+
+    test("records parameters as case-insensitive", () {
+      var type = new MediaType.parse('test/plain;FoO=bar;bAz=bang');
+      expect(type.parameters, equals({
+        "FoO": "bar",
+        "bAz": "bang"
+      }));
+      expect(type.parameters, containsPair("foo", "bar"));
+      expect(type.parameters, containsPair("baz", "bang"));
+    });
   });
 
   group("change", () {
     var type;
     setUp(() {
       type = new MediaType.parse("text/plain; foo=bar; baz=bang");
     });
 
     test("uses the existing fields by default", () {
       var newType = type.change();
@@ skipping 62 matching lines @@
       expect(new MediaType("text", "plain", {"foo": 'bar"\x7Fbaz'}).toString(),
           equals('text/plain; foo="bar\\"\\\x7Fbaz"'));
     });
 
     test("serializes multiple parameters", () {
       expect(new MediaType("text", "plain", {"foo": "bar", "baz": "bang"})
           .toString(), equals("text/plain; foo=bar; baz=bang"));
     });
   });
 }