Feature/sbachmei/mic 5127 update standard observers (#441)

* reset index in default results_formatter

* handle some .astype() warnings

* more observers configuration_defaults stratification name into getter method

src/vivarium/framework/results/interface.py

@@ -319,7 +319,7 @@ def register_adding_observation(
         requires_values: List[str] = [],
         results_formatter: Callable[
             [str, pd.DataFrame], pd.DataFrame
-        ] = lambda measure, results: results,
+        ] = lambda measure, results: results.reset_index(),
         additional_stratifications: List[str] = [],
         excluded_stratifications: List[str] = [],
         aggregator_sources: Optional[List[str]] = None,

src/vivarium/framework/results/observation.py

@@ -136,11 +136,13 @@ def initialize_results(
             df = pd.DataFrame(
                 list(itertools.product(*stratification_values.values())),
                 columns=stratification_names,
-            ).astype(CategoricalDtype)
+            ).astype(CategoricalDtype())
         else:
             # We are aggregating the entire population so create a single-row index
             stratification_names = ["stratification"]
-            df = pd.DataFrame(["all"], columns=stratification_names).astype(CategoricalDtype)
+            df = pd.DataFrame(["all"], columns=stratification_names).astype(
+                CategoricalDtype()
+            )
 
         # Initialize a zeros dataframe
         df[VALUE_COLUMN] = 0.0
@@ -170,7 +172,7 @@ def _aggregate(
             pop_groups[aggregator_sources].apply(aggregator).fillna(0.0)
             if aggregator_sources
             else pop_groups.apply(aggregator)
-        )
+        ).astype(float)
         return aggregates
 
     @staticmethod

src/vivarium/framework/results/observer.py

@@ -21,13 +21,16 @@ def __init__(self) -> None:
     def configuration_defaults(self) -> Dict[str, Any]:
         return {
             "stratification": {
-                self.name.split("_observer")[0]: {
+                self.get_configuration_name(): {
                     "exclude": [],
                     "include": [],
                 },
             },
         }
 
+    def get_configuration_name(self) -> str:
+        return self.name.split("_observer")[0]
+
     @abstractmethod
     def register_observations(self, builder: Builder) -> None:
         """(Required). Register observations with within each observer."""