Cleanup code and add tests

SDESK-7459

superdesk/core/privileges.py

@@ -1,4 +1,3 @@
-from typing import cast
 from dataclasses import dataclass
 from quart_babel.speaklater import LazyString
 
@@ -12,17 +11,18 @@ class Privilege:
 
 
 class PrivilegesRegistry:
-    __privileges: set[Privilege] | frozenset[Privilege] = set()
+    __privileges: set[Privilege] | frozenset[Privilege]
+
+    def __init__(self):
+        self.__privileges = set()
 
     def add(self, privilege: Privilege):
         """Add a privilege if the registry is not locked."""
 
         if self.is_locked:
             raise RuntimeError("Cannot add privileges after the app has started.")
 
-        # mypy does not pick the `is_locked` condition
-        self.__privileges = cast(set[Privilege], self.__privileges)
-        self.__privileges.add(privilege)
+        self.__privileges.add(privilege)  # type: ignore[union-attr]
 
     @property
     def is_locked(self):

tests/core/privileges_registry_test.py

@@ -0,0 +1,65 @@
+import pytest
+from superdesk.core.privileges import PrivilegesRegistry, Privilege
+
+
+@pytest.fixture(scope="function")
+def registry():
+    reg = PrivilegesRegistry()
+    yield reg
+
+    print("*" * 100)
+    reg = None
+
+
+def test_add_privilege_before_lock(registry):
+    privilege = Privilege(name="edit_article")
+
+    registry.add(privilege)
+
+    assert "edit_article" in registry
+    assert registry.get_all() == [privilege]
+
+
+def test_add_multiple_privileges(registry):
+    privilege1 = Privilege(name="edit_article")
+    privilege2 = Privilege(name="delete_article")
+
+    registry.add(privilege1)
+    registry.add(privilege2)
+
+    assert "edit_article" in registry
+    assert "delete_article" in registry
+    assert len(registry.get_all()) == 2
+
+
+def test_lock_registry(registry):
+    privilege = Privilege(name="edit_article")
+
+    registry.add(privilege)
+    registry.lock()
+
+    assert registry.is_locked
+    assert "edit_article" in registry
+
+
+def test_cannot_add_after_lock(registry):
+    privilege = Privilege(name="edit_article")
+
+    registry.add(privilege)
+    registry.lock()
+
+    with pytest.raises(RuntimeError):
+        registry.add(Privilege(name="new_privilege"))
+
+
+def test_lock_prevents_further_additions(registry):
+    privilege = Privilege(name="edit_article")
+
+    registry.add(privilege)
+    registry.lock()
+
+    with pytest.raises(RuntimeError, match="Cannot add privileges after the app has started."):
+        registry.add(Privilege(name="new_privilege"))
+
+    assert len(registry.get_all()) == 1
+    assert registry.is_locked