[test] fix incoming test with the new async blobs backend

tests/server/test_incoming_server.py

@@ -84,12 +84,12 @@ class IncomingOnCouchServerTestCase(CouchDBTestCase):
 
         db = self.state.open_database(user_id)
         request = DummyRequest([user_id, doc_id])
-        res = db.read_blob(user_id, doc_id, namespace='MX')
-        yield res.render_GET(request)
-        flags = db.get_flags(user_id, doc_id, namespace='MX')
+        fd = yield db.read_blob(user_id, doc_id, namespace='MX')
+        flags = yield db.get_flags(user_id, doc_id, namespace='MX')
+        data = fd.read()
         expected_preamble = formatter.preamble(content, doc_id)
         expected_preamble = decode_preamble(expected_preamble, True)
-        written_preamble, written_content = request.written[0].split()
+        written_preamble, written_content = data.split()
         written_preamble = decode_preamble(written_preamble, True)
         self.assertEquals(expected_preamble, written_preamble)
         self.assertEquals(content, written_content)