[FSSDK-12265] Add experiments field and mapping to Holdout data model

- Add experiments field to Holdout entity with default empty list
- Add is_local property that returns True when experiments list is not empty
- Add experiment_holdouts_map to ProjectConfig for experiment-to-holdout mappings
- Add get_holdouts_for_experiment method to retrieve holdouts for a specific experiment
- Add comprehensive unit tests covering all new functionality
- Ensure backward compatibility with existing holdout functionality

This enables experiment-specific holdouts to be identified and retrieved efficiently.

Author: muzahidul-opti

optimizely/entities.py

@@ -223,6 +223,7 @@ def __init__(
         includedFlags: Optional[list[str]] = None,
         excludedFlags: Optional[list[str]] = None,
         audienceConditions: Optional[Sequence[str | list[str]]] = None,
+        experiments: Optional[list[str]] = None,
         **kwargs: Any
     ):
         self.id = id
@@ -234,6 +235,7 @@ def __init__(
         self.audienceConditions = audienceConditions
         self.includedFlags = includedFlags or []
         self.excludedFlags = excludedFlags or []
+        self.experiments = experiments or []
 
     def get_audience_conditions_or_ids(self) -> Sequence[str | list[str]]:
         """Returns audienceConditions if present, otherwise audienceIds.
@@ -255,6 +257,19 @@ def is_activated(self) -> bool:
         """
         return self.status == self.Status.RUNNING
 
+    @property
+    def is_local(self) -> bool:
+        """Check if the holdout is local (experiment-specific).
+
+        A holdout is considered local if it targets specific experiments.
+        Matches Swift's isLocal computed property:
+        var isLocal: Bool { return !experiments.isEmpty }
+
+        Returns:
+            True if experiments list is not empty, False otherwise.
+        """
+        return len(self.experiments) > 0
+
     def __str__(self) -> str:
         return self.key
 

optimizely/helpers/types.py

@@ -128,3 +128,4 @@ class HoldoutDict(ExperimentDict):
     holdoutStatus: HoldoutStatus
     includedFlags: list[str]
     excludedFlags: list[str]
+    experiments: list[str]

optimizely/project_config.py

@@ -97,6 +97,7 @@ def __init__(self, datafile: str | bytes, logger: Logger, error_handler: Any):
         self.included_holdouts: dict[str, list[entities.Holdout]] = {}
         self.excluded_holdouts: dict[str, list[entities.Holdout]] = {}
         self.flag_holdouts_map: dict[str, list[entities.Holdout]] = {}
+        self.experiment_holdouts_map: dict[str, list[entities.Holdout]] = {}
 
         # Convert holdout dicts to Holdout entities
         for holdout_data in holdouts_data:
@@ -131,6 +132,13 @@ def __init__(self, datafile: str | bytes, logger: Logger, error_handler: Any):
                         self.included_holdouts[flag_id] = []
                     self.included_holdouts[flag_id].append(holdout)
 
+            # Build experiment-to-holdout mappings for local holdouts
+            if holdout.experiments:
+                for experiment_id in holdout.experiments:
+                    if experiment_id not in self.experiment_holdouts_map:
+                        self.experiment_holdouts_map[experiment_id] = []
+                    self.experiment_holdouts_map[experiment_id].append(holdout)
+
         # Utility maps for quick lookup
         self.group_id_map: dict[str, entities.Group] = self._generate_key_map(self.groups, 'id', entities.Group)
         self.experiment_id_map: dict[str, entities.Experiment] = self._generate_key_map(
@@ -876,3 +884,18 @@ def get_holdout(self, holdout_id: str) -> Optional[entities.Holdout]:
 
         self.logger.error(f'Holdout with ID "{holdout_id}" not found.')
         return None
+
+    def get_holdouts_for_experiment(self, experiment_id: str) -> list[entities.Holdout]:
+        """ Helper method to get holdouts targeting a specific experiment.
+
+        Args:
+            experiment_id: ID of the experiment.
+
+        Returns:
+            The holdouts that apply to this experiment as Holdout entity objects.
+            Returns empty list if no holdouts target this experiment.
+        """
+        if not self.holdouts:
+            return []
+
+        return self.experiment_holdouts_map.get(experiment_id, [])