diff --git a/src/yunohost/app.py b/src/yunohost/app.py
index 4ec043687..4abaaecca 100644
--- a/src/yunohost/app.py
+++ b/src/yunohost/app.py
@@ -2429,7 +2429,7 @@ class YunoHostArgumentFormatParser(object):
             if not question.optional and question.default is None:
                 raise YunohostError('app_argument_required', name=question.name)
             else:
-                question.value = self.default_value if question.default is None else question.default
+                question.value = getattr(self, "default_value", None) if question.default is None else question.default
 
         # we have an answer, do some post checks
         if question.value is not None:
diff --git a/src/yunohost/tests/test_apps_arguments_parsing.py b/src/yunohost/tests/test_apps_arguments_parsing.py
index 7b835c410..1ea73cc0a 100644
--- a/src/yunohost/tests/test_apps_arguments_parsing.py
+++ b/src/yunohost/tests/test_apps_arguments_parsing.py
@@ -1011,14 +1011,14 @@ def test_parse_args_in_yunohost_format_app_no_apps():
             _parse_args_in_yunohost_format(answers, questions)
 
 
-@pytest.mark.skip  # XXX should work
 def test_parse_args_in_yunohost_format_app_no_apps_optional():
     apps = []
     questions = [{"name": "some_app", "type": "app", "optional": True}]
     answers = {}
+    expected_result = OrderedDict({"some_app": (None, "app")})
 
     with patch.object(app, "app_list", return_value={"apps": apps}):
-        assert _parse_args_in_yunohost_format(answers, questions) == []
+        assert _parse_args_in_yunohost_format(answers, questions) == expected_result
 
 
 def test_parse_args_in_yunohost_format_app():