diff --git a/tests/testutil.py b/tests/testutil.py
index f4ef5e8b687fcb076158360a46a3564225851c02..7eaf304ca8cb22d8f803269fffcf4ab61104de58 100644
--- a/tests/testutil.py
+++ b/tests/testutil.py
@@ -55,6 +55,11 @@ def combine_values(*value_seqs):
         stop,
     )
 
+def date_seq(date=FY_MID_DATE, step=1):
+    while True:
+        yield date
+        date += datetime.timedelta(days=step)
+
 def parse_date(s, fmt='%Y-%m-%d'):
     return datetime.datetime.strptime(s, fmt).date()