To keep work scoped, add masking strategy override to CollectionMeta,…

… removing it from field and dataset level meta.

- Constrain the masking strategies into an enum.

src/fideslang/models.py

@@ -62,8 +62,12 @@
 )
 
 
-class MaskingStrategy(BaseModel):
-    strategy: str
+class MaskingStrategies(str, Enum):
+    delete = "delete"
+
+
+class MaskingStrategyOverride(BaseModel):
+    strategy: MaskingStrategies
 
 
 class FidesModel(BaseModel):
@@ -410,7 +414,6 @@ class FidesMeta(BaseModel):
         default=None,
         description="Optionally specify that a field may be used as a custom request field in DSRs. The value is the name of the field in the DSR.",
     )
-    masking_strategy_override: Optional[MaskingStrategy] = None
 
     @field_validator("data_type")
     @classmethod
@@ -521,7 +524,7 @@ class CollectionMeta(BaseModel):
 
     after: Optional[List[FidesCollectionKey]] = None
     skip_processing: Optional[bool] = False
-    masking_strategy_override: Optional[MaskingStrategy] = None
+    masking_strategy_override: Optional[MaskingStrategyOverride] = None
 
 
 class DatasetCollection(FidesopsMetaBackwardsCompat):
@@ -585,7 +588,6 @@ class DatasetMetadata(BaseModel):
 
     resource_id: Optional[str] = None
     after: Optional[List[FidesKey]] = None
-    masking_strategy_override: Optional[MaskingStrategy] = None
 
 
 class Dataset(FidesModel, FidesopsMetaBackwardsCompat):

tests/fideslang/test_validation.py

@@ -15,6 +15,8 @@
     FidesDatasetReference,
     FidesMeta,
     FidesModel,
+    MaskingStrategies,
+    MaskingStrategyOverride,
     Policy,
     PolicyRule,
     PrivacyDeclaration,
@@ -642,7 +644,7 @@ def test_specify_fides_meta_with_custom_request_field(self):
             length=None,
             return_all_elements=None,
             read_only=None,
-            custom_request_field="site_id"
+            custom_request_field="site_id",
         )
 
     def test_specify_both_fidesops_meta_and_fides_meta(self):
@@ -789,6 +791,13 @@ def test_collection_key_has_too_many_components(self):
     def test_valid_collection_key(self):
         CollectionMeta(after=[FidesCollectionKey("test_dataset.test_collection")])
 
+    def test_(self):
+        meta = CollectionMeta(masking_strategy_override={"strategy": "delete"})
+
+        assert meta.masking_strategy_override == MaskingStrategyOverride(
+            strategy=MaskingStrategies.delete
+        )
+
 
 class TestAnyUrlString:
     def test_valid_url(self):