fix(metrics): AttributeError raises when setting metadata_set

Author: Michael Brewer

aws_lambda_powertools/metrics/base.py

@@ -88,7 +88,7 @@ def __init__(
         self.service = resolve_env_var_choice(choice=service, env=os.getenv(constants.SERVICE_NAME_ENV))
         self._metric_units = [unit.value for unit in MetricUnit]
         self._metric_unit_options = list(MetricUnit.__members__)
-        self.metadata_set = self.metadata_set if metadata_set is not None else {}
+        self.metadata_set = metadata_set if metadata_set is not None else {}
 
     def add_metric(self, name: str, unit: Union[MetricUnit, str], value: float):
         """Adds given metric

tests/functional/test_metrics.py

@@ -739,3 +739,13 @@ def test_serialize_metric_set_metric_definition_multiple_values(
     assert "Timestamp" in metric_definition_output["_aws"]
     remove_timestamp(metrics=[metric_definition_output, expected_metric_definition])
     assert metric_definition_output == expected_metric_definition
+
+
+def test_metric_manage_metadata_set():
+    expected_dict = {"setting": "On"}
+
+    try:
+        metric = MetricManager(metadata_set=expected_dict)
+        assert metric.metadata_set == expected_dict
+    except AttributeError:
+        pytest.fail("AttributeError should not be raised")