fix mutable default argument in StateItem metadata

dapr/clients/grpc/_state.py

@@ -59,7 +59,7 @@ def __init__(
         value: Union[bytes, str],
         etag: Optional[str] = None,
         options: Optional[StateOptions] = None,
-        metadata: Optional[Dict[str, str]] = dict(),
+        metadata: Optional[Dict[str, str]] = None,
     ):
         """Inits StateItem with the required parameters.
 
@@ -80,7 +80,7 @@ def __init__(
         self._value = value
         self._etag = etag
         self._options = options
-        self._metadata = metadata
+        self._metadata = metadata if metadata is not None else {}
 
     @property
     def key(self):

tests/clients/test_state.py

@@ -0,0 +1,33 @@
+#!/usr/bin/env python3
+
+"""
+Unit tests for the StateItem class.
+"""
+
+import unittest
+
+from dapr.clients.grpc._state import StateItem
+
+
+class TestStateItem(unittest.TestCase):
+    """Test cases for StateItem."""
+
+    def test_metadata_defaults_to_empty_dict(self):
+        item = StateItem(key='key1', value='value1')
+        self.assertEqual(item.metadata, {})
+
+    def test_metadata_not_shared_between_instances(self):
+        item1 = StateItem(key='key1', value='value1')
+        item2 = StateItem(key='key2', value='value2')
+
+        item1.metadata['injected'] = 'value'
+
+        self.assertNotIn('injected', item2.metadata)
+
+    def test_metadata_uses_provided_value(self):
+        item = StateItem(key='key1', value='value1', metadata={'k': 'v'})
+        self.assertEqual(item.metadata, {'k': 'v'})
+
+
+if __name__ == '__main__':
+    unittest.main()