refactoring the mixin system

tests/mixins/metadata_tests.py

@@ -0,0 +1,68 @@
+"""
+Test mixins for MetadataContainer functionality.
+
+Provides reusable test cases for any class that uses the MetadataContainer mixin.
+"""
+
+
+class MetadataContainerTestMixin:
+    """
+    Mixin providing standard tests for MetadataContainer behavior.
+
+    Classes using this mixin must implement:
+    - create_test_object() -> object with MetadataContainer mixin
+    """
+
+    def create_test_object(self):
+        """
+        Create an instance of the object to test.
+        Must be implemented by test class.
+        """
+        raise NotImplementedError("Test class must implement create_test_object()")
+
+    def test_set_and_get_metadata(self):
+        """Test basic metadata storage and retrieval."""
+        obj = self.create_test_object()
+
+        # Set various types of metadata
+        obj.set_metadata("string_key", "string_value")
+        obj.set_metadata("int_key", 42)
+        obj.set_metadata("list_key", [1, 2, 3])
+        obj.set_metadata("dict_key", {"nested": "value"})
+
+        # Verify retrieval
+        self.assertEqual(obj.get_metadata("string_key"), "string_value")
+        self.assertEqual(obj.get_metadata("int_key"), 42)
+        self.assertEqual(obj.get_metadata("list_key"), [1, 2, 3])
+        self.assertEqual(obj.get_metadata("dict_key"), {"nested": "value"})
+
+    def test_get_nonexistent_metadata(self):
+        """Test that getting nonexistent metadata returns None."""
+        obj = self.create_test_object()
+
+        result = obj.get_metadata("nonexistent_key")
+        self.assertIsNone(result, "Nonexistent metadata should return None")
+
+    def test_update_metadata(self):
+        """Test that metadata values can be updated."""
+        obj = self.create_test_object()
+
+        # Set initial value
+        obj.set_metadata("key", "initial")
+        self.assertEqual(obj.get_metadata("key"), "initial")
+
+        # Update value
+        obj.set_metadata("key", "updated")
+        self.assertEqual(obj.get_metadata("key"), "updated", "Metadata should be updateable")
+
+    def test_metadata_isolation(self):
+        """Test that metadata is isolated between instances."""
+        obj1 = self.create_test_object()
+        obj2 = self.create_test_object()
+
+        obj1.set_metadata("key", "value1")
+        obj2.set_metadata("key", "value2")
+
+        self.assertEqual(obj1.get_metadata("key"), "value1")
+        self.assertEqual(obj2.get_metadata("key"), "value2")
+        self.assertNotEqual(obj1.get_metadata("key"), obj2.get_metadata("key"))