diff --git a/tolaria/c5-sync-service/test_c5a.py b/tolaria/c5-sync-service/test_c5a.py
index 6ccb441..affcb71 100644
--- a/tolaria/c5-sync-service/test_c5a.py
+++ b/tolaria/c5-sync-service/test_c5a.py
@@ -41,6 +41,7 @@ from rq_c5a import (
     RC_UNKNOWN_LEGACY_OBJECT, RC_AUTH_FAILURE, RC_SEARCH_REBUILD_FAILURE,
     RC_TOLARIA_UNAVAILABLE, RC_FORGEJO_UNAVAILABLE,
     RC_SEARCH_UNAVAILABLE, RC_NETWORK_TIMEOUT, RC_MALFORMED_RESPONSE, RC_INTEGRITY_FAILURE,
+    RC_SEARCH_SOURCE_BUILD_FAILURE,
     REASON_CODES, OPERATIONS, SYNC_STATES, BOOTSTRAP_STATES,
 )
 
@@ -330,7 +331,9 @@ def test_reason_codes_closed_set():
     assert RC_NETWORK_TIMEOUT in REASON_CODES
     assert RC_MALFORMED_RESPONSE in REASON_CODES
     assert RC_INTEGRITY_FAILURE in REASON_CODES
-    assert len(REASON_CODES) == 17
+    # C5D-Erweiterung (search-source pipeline, commit 5e41915)
+    assert RC_SEARCH_SOURCE_BUILD_FAILURE in REASON_CODES
+    assert len(REASON_CODES) == 18
     store = _new_store()
     try:
         store.set_commit_error("c1", "FREIER_STRING", "x")