--- a/Lib/test/test_httpservers.py	Sun Nov 21 13:56:42 2010 +0000
+++ b/Lib/test/test_httpservers.py	Sun Nov 21 14:36:14 2010 +0000
@@ -511,6 +511,49 @@
         self.verify_get_called()
         self.assertEqual(result[-1], b'<html><body>Data</body></html>\r\n')
 
+    def test_header_buffering(self):
+
+        def _readAndReseek(f):
+            pos = f.tell()
+            f.seek(0)
+            data = f.read()
+            f.seek(pos)
+            return data
+
+        input = BytesIO(b'GET / HTTP/1.1\r\n\r\n')
+        output = BytesIO()
+        self.handler.rfile = input
+        self.handler.wfile = output
+        self.handler.request_version = 'HTTP/1.1'
+
+        self.handler.send_header('Foo', 'foo')
+        self.handler.send_header('bar', 'bar')
+        self.assertEqual(_readAndReseek(output), b'')
+        self.handler.end_headers()
+        self.assertEqual(_readAndReseek(output),
+                         b'Foo: foo\r\nbar: bar\r\n\r\n')
+
+    def test_header_unbuffered_when_continue(self):
+
+        def _readAndReseek(f):
+            pos = f.tell()
+            f.seek(0)
+            data = f.read()
+            f.seek(pos)
+            return data
+
+        input = BytesIO(b'GET / HTTP/1.1\r\nExpect: 100-continue\r\n\r\n')
+        output = BytesIO()
+        self.handler.rfile = input
+        self.handler.wfile = output
+        self.handler.request_version = 'HTTP/1.1'
+
+        self.handler.handle_one_request()
+        self.assertNotEqual(_readAndReseek(output), b'')
+        result = _readAndReseek(output).split(b'\r\n')
+        self.assertEqual(result[0], b'HTTP/1.1 100 Continue')
+        self.assertEqual(result[1], b'HTTP/1.1 200 OK')
+
     def test_with_continue_rejected(self):
         usual_handler = self.handler        # Save to avoid breaking any subsequent tests.
         self.handler = RejectingSocketlessRequestHandler()