diff --git a/workflow/tests/test_experiment_design.py b/workflow/tests/test_experiment_design.py
index 39ab570a409a004594656a47856bf5015759aaa3..508dbb12f7588a41622aff7eca1d58a4bc31a1ac 100644
--- a/workflow/tests/test_experiment_design.py
+++ b/workflow/tests/test_experiment_design.py
@@ -4,6 +4,7 @@ import pytest
 import pandas as pd
 from io import StringIO
 import experiment_design
+import os
 
 test_output_path = os.path.dirname(os.path.abspath(__file__)) + \
                 '/../output/design/'