diff --git a/spinn_utilities/config_setup.py b/spinn_utilities/config_setup.py
index f42a411a..c03ba5a1 100644
--- a/spinn_utilities/config_setup.py
+++ b/spinn_utilities/config_setup.py
@@ -15,6 +15,7 @@
 import os
 from spinn_utilities.config_holder import (
     add_default_cfg, clear_cfg_files)
+from spinn_utilities.data.utils_data_writer import UtilsDataWriter
 
 BASE_CONFIG_FILE = "spinn_utilities.cfg"
 
@@ -30,6 +31,7 @@ def unittest_setup():
     """
     clear_cfg_files(True)
     add_spinn_utilities_cfg()
+    UtilsDataWriter.mock()
 
 
 def add_spinn_utilities_cfg():