diff --git a/tobac/tests/test_iris_xarray_match_utils.py b/tobac/tests/test_iris_xarray_match_utils.py
index b56b3f54..84e00f3f 100644
--- a/tobac/tests/test_iris_xarray_match_utils.py
+++ b/tobac/tests/test_iris_xarray_match_utils.py
@@ -2,6 +2,8 @@
  for the same input datasets.
 """
 
+from __future__ import annotations
+
 import copy
 import datetime