pkg/shelf: case-insensitive headers, cleaner Request ctor, a lot more tests

pkg/shelf/test/shelf_io_test.dart

Index: pkg/shelf/test/shelf_io_test.dart
diff --git a/pkg/shelf/test/shelf_io_test.dart b/pkg/shelf/test/shelf_io_test.dart
index 1fa0e96f4642623b417d888aa4927c29d0967a0e..44f0dc50226cf7824fd0c6a77d1516ba80225955 100644
--- a/pkg/shelf/test/shelf_io_test.dart
+++ b/pkg/shelf/test/shelf_io_test.dart
@@ -129,11 +129,16 @@ void main() {
   test('custom request headers are received by the handler', () {
     _scheduleServer((request) {
       expect(request.headers, containsPair('custom-header', 'client value'));
+
+      // dart:io HttpServer splits multi-value headers into an array
+      // validate that they are combined correctly
+      expect(request.headers, containsPair('multi-header', 'foo,bar,baz'));
       return syncHandler(request);
     });
 
     var headers = {
-      'custom-header': 'client value'
+      'custom-header': 'client value',
+      'multi-header': 'foo,bar,baz'

[nweiz, 2014/04/08 20:23:09]

Does dart:io really split comma-separated header values? I thought it considered
multiple headers with the same name as separate.

[kevmoo, 2014/04/08 21:41:13]

HttpHeaders stores values in a List. shelf_io does a join to turn them back into
a string. This is just checked to make sure the round-trip is valid.

     };
 
     return _scheduleGet(headers: headers).then((response) {