diff --git a/workflow/tests/test_pool_and_psuedoreplicate.py b/workflow/tests/test_pool_and_psuedoreplicate.py
index 6f99dcdc433d131cd2502f214ebbe92ca4a55a79..ef8d268cf1c2ab819a84a5f9338d63df5f746a9d 100644
--- a/workflow/tests/test_pool_and_psuedoreplicate.py
+++ b/workflow/tests/test_pool_and_psuedoreplicate.py
@@ -63,7 +63,7 @@ def test_check_controls_single(design_experiment_3):
 @pytest.mark.unit
 def test_single_rep(design_experiment_2):
     cwd = os.getcwd()
-    B_1 = open(cwd + 'B_1.bedse.gz')
+    B_1 = open(cwd + '/B_1.bedse.gz', "w+")
     B_1.close()
     single_rep = pool_and_psuedoreplicate.generate_design('false', 1.2, design_experiment_2, cwd, 1, 1)