add app setting user_modifiable validation (#1536)

CHANGELOG.rst

@@ -16,6 +16,7 @@ Added
     - App setting type constants (#1458)
     - ``PluginAppSettingDef`` class for app setting definitions (#1456)
     - Django check for unique app setting names within each plugin (#1456)
+    - App setting ``user_modifiable`` validation (#1536)
 
 Changed
 -------

projectroles/plugins.py

@@ -671,7 +671,7 @@ def __init__(
         placeholder=None,
         description=None,
         options=None,
-        user_modifiable=True,
+        user_modifiable=None,  # Set None here to validate PROJECT_USER value
         global_edit=False,
         project_types=None,
         widget_attrs=None,
@@ -714,6 +714,12 @@ def __init__(
             and not callable(options)
         ):
             self.validate_default_in_options(default, options)
+        # Validate and set user_modifiable
+        self.validate_user_modifiable(scope, user_modifiable)
+        if user_modifiable is None:
+            user_modifiable = (
+                False if scope == APP_SETTING_SCOPE_PROJECT_USER else True
+            )
         # Set members
         self.name = name
         self.scope = scope
@@ -830,6 +836,21 @@ def validate_value(cls, setting_type, setting_value):
                     'Please enter valid JSON ({})'.format(setting_value)
                 )
 
+    @classmethod
+    def validate_user_modifiable(cls, scope, user_modifiable):
+        """
+        Validate user_modifiable against scope.
+
+        :param scope: String
+        :param user_modifiable: Bool or None
+        :raises: ValueError if user_modifiable can't be set for scope
+        """
+        if user_modifiable and scope == APP_SETTING_SCOPE_PROJECT_USER:
+            raise ValueError(
+                'Argument user_modifiable can not be set True for PROJECT_USER '
+                'scope settings'
+            )
+
 
 class PluginObjectLink:
     """

projectroles/tests/test_plugins.py

@@ -249,3 +249,37 @@ def test_init_default_not_in_options(self):
                 default=0,
                 options=[1, 2],
             )
+
+    def test_init_project_user_modifiable_false(self):
+        """Test init with PROJECT_USER scope and user_modifiable=False"""
+        s_def = PluginAppSettingDef(
+            name=DEF_NAME,
+            scope=APP_SETTING_SCOPE_PROJECT_USER,
+            type=APP_SETTING_TYPE_BOOLEAN,
+            default=True,
+            user_modifiable=False,
+        )
+        self.assertIsNotNone(s_def)
+        self.assertEqual(s_def.user_modifiable, False)
+
+    def test_init_project_user_modifiable_unset(self):
+        """Test init with PROJECT_USER scope and user_modifiable unset"""
+        s_def = PluginAppSettingDef(
+            name=DEF_NAME,
+            scope=APP_SETTING_SCOPE_PROJECT_USER,
+            type=APP_SETTING_TYPE_BOOLEAN,
+            default=True,
+        )
+        self.assertIsNotNone(s_def)
+        self.assertEqual(s_def.user_modifiable, False)
+
+    def test_init_project_user_modifiable_true(self):
+        """Test init with PROJECT_USER scope and user_modifiable=True"""
+        with self.assertRaises(ValueError):
+            PluginAppSettingDef(
+                name=DEF_NAME,
+                scope=APP_SETTING_SCOPE_PROJECT_USER,
+                type=APP_SETTING_TYPE_BOOLEAN,
+                default=True,
+                user_modifiable=True,
+            )