diff --git a/workflow/tests/test_pool_and_psuedoreplicate.py b/workflow/tests/test_pool_and_psuedoreplicate.py
index cb8842c178fcb5b03055e5175543ee238ad175eb..06056d5177038b10122289cf78344123768bfd21 100644
--- a/workflow/tests/test_pool_and_psuedoreplicate.py
+++ b/workflow/tests/test_pool_and_psuedoreplicate.py
@@ -64,7 +64,7 @@ def test_check_controls_single(design_experiment_3):
 @pytest.mark.unit
 def test_single_rep(design_experiment_2):
     sys.argv.extend(['-d', design_experiment_2])
-    sys.argv.extend(['-p', true])
+    sys.argv.extend(['-p', 'true'])
     sys.argv.extend(['-c', 1.2])
     single_rep = pool_and_psuedoreplicate.main()