diff --git a/tests/test_load.py b/tests/test_load.py
index b39f673..444db17 100644
--- a/tests/test_load.py
+++ b/tests/test_load.py
@@ -98,7 +98,12 @@ def populate(dest_dir, rougailconfig):
                 root_config = config.unrestraint
             else:
                 root_config = config.unrestraint.value.mandatory()
-            values = ['ROUGAIL_' + variable.path().upper() + '="' + "" if get_value(variable) is None else get_value(variable) + '"' for variable in get_variables(root_config)]
+            values = []
+            for variable in get_variables(root_config):
+                var = get_value(variable)
+                if var is None:
+                    var = ""
+                values.append('ROUGAIL_' + variable.path().upper() + '="' + var + '"')
         if not environment_file.is_file():
             with environment_file.open('w') as envfh:
                 envfh.write('\n'.join(values) + '\n')