diff --git a/tests/test_tui.py b/tests/test_tui.py
index 6a975d7..d7e3023 100644
--- a/tests/test_tui.py
+++ b/tests/test_tui.py
@@ -109,6 +109,7 @@ def _insert_sample(conn, ts, pu=5, device="/dev/nvme0n1"):
 
 def _open_period(conn, start="2026-09-01T00:00:00+00:00"):
     ensure_period_open(conn, datetime.fromisoformat(start))
+    conn.commit()
 
 
 def _insert_local_day(conn, local_date, tz_name="UTC", tz_offset="+00:00",