diff --git a/build/source_list.gni b/build/source_list.gni
index 1b35497..3deabbd 100644
--- a/build/source_list.gni
+++ b/build/source_list.gni
@@ -822,6 +822,7 @@
     "src/quiche/quic/test_tools/simulator/quic_endpoint_base.h",
     "src/quiche/quic/test_tools/simulator/simulator.h",
     "src/quiche/quic/test_tools/simulator/switch.h",
+    "src/quiche/quic/test_tools/simulator/test_harness.h",
     "src/quiche/quic/test_tools/simulator/traffic_policer.h",
     "src/quiche/quic/test_tools/test_certificates.h",
     "src/quiche/quic/test_tools/test_ticket_crypter.h",
@@ -916,6 +917,7 @@
     "src/quiche/quic/test_tools/simulator/quic_endpoint_base.cc",
     "src/quiche/quic/test_tools/simulator/simulator.cc",
     "src/quiche/quic/test_tools/simulator/switch.cc",
+    "src/quiche/quic/test_tools/simulator/test_harness.cc",
     "src/quiche/quic/test_tools/simulator/traffic_policer.cc",
     "src/quiche/quic/test_tools/test_certificates.cc",
     "src/quiche/quic/test_tools/test_ticket_crypter.cc",