diff --git a/quic/test_tools/quic_connection_peer.cc b/quic/test_tools/quic_connection_peer.cc
index 100fe15..953e495 100644
--- a/quic/test_tools/quic_connection_peer.cc
+++ b/quic/test_tools/quic_connection_peer.cc
@@ -351,5 +351,11 @@
   return connection->current_packet_content_;
 }
 
+// static
+void QuicConnectionPeer::SetLastHeaderFormat(QuicConnection* connection,
+                                             PacketHeaderFormat format) {
+  connection->last_header_.form = format;
+}
+
 }  // namespace test
 }  // namespace quic