diff --git a/tests/conftest.py b/tests/conftest.py
index 536a2ef..3bdf601 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -9,7 +9,9 @@
 data_file_path = os.path.dirname(__file__) + "/sample_data/"
 
 
-CifData = namedtuple("CifData", ["filename", "symop_keys", "atom_site_keys"])
+CifData = namedtuple(
+    "CifData", ["filename", "symop_keys", "atom_site_keys", "single_value_keys"]
+)
 
 # Assorted keys to select from
 assorted_keys = np.loadtxt(data_file_path + "cif_file_keys.txt", dtype=str)