diff --git a/quic/test_tools/quic_connection_peer.h b/quic/test_tools/quic_connection_peer.h
index 5b97ae6..c5c972f 100644
--- a/quic/test_tools/quic_connection_peer.h
+++ b/quic/test_tools/quic_connection_peer.h
@@ -139,6 +139,10 @@
                                   PacketHeaderFormat format);
   static void AddBytesReceived(QuicConnection* connection, size_t length);
   static void SetAddressValidated(QuicConnection* connection);
+
+  static void SendConnectionClosePacket(QuicConnection* connection,
+                                        QuicErrorCode error,
+                                        const std::string& details);
 };
 
 }  // namespace test