Silo test helpers support app_name, making them easier to apply to (#44649)

Follow up will be applying the `test_silo_models` tests to getsentry.

src/sentry/testutils/silo.py

@@ -198,22 +198,23 @@ def restrict_role(role: str, model: Any, revocation_type: str) -> None:
         connection.execute(f"REVOKE {revocation_type} ON public.{model._meta.db_table} FROM {role}")
 
 
-def iter_models() -> Iterable[Type[Model]]:
+def iter_models(app_name: str | None = None) -> Iterable[Type[Model]]:
     from django.apps import apps
 
     for app, app_models in apps.all_models.items():
-        for model in app_models.values():
-            if (
-                model.__module__.startswith("django.")
-                or "tests." in model.__module__
-                or "fixtures." in model.__module__
-            ):
-                continue
-            yield model
+        if app == app_name or app_name is None:
+            for model in app_models.values():
+                if (
+                    model.__module__.startswith("django.")
+                    or "tests." in model.__module__
+                    or "fixtures." in model.__module__
+                ):
+                    continue
+                yield model
 
 
-def validate_models_have_silos(exemptions: Set[Type[Model]]) -> None:
-    for model in iter_models():
+def validate_models_have_silos(exemptions: Set[Type[Model]], app_name: str | None = None) -> None:
+    for model in iter_models(app_name):
         if model in exemptions:
             continue
         if not isinstance(getattr(model._meta, "silo_limit", None), ModelSiloLimit):
@@ -229,13 +230,17 @@ def validate_models_have_silos(exemptions: Set[Type[Model]]) -> None:
             )
 
 
-def validate_no_cross_silo_foreign_keys(exemptions: Set[Tuple[Type[Model], Type[Model]]]) -> None:
-    for model in iter_models():
+def validate_no_cross_silo_foreign_keys(
+    exemptions: Set[Tuple[Type[Model], Type[Model]]], app_name: str | None = None
+) -> None:
+    for model in iter_models(app_name):
         validate_model_no_cross_silo_foreign_keys(model, exemptions)
 
 
-def validate_no_cross_silo_deletions(exemptions: Set[Tuple[Type[Model], Type[Model]]]) -> None:
-    for model_class in iter_models():
+def validate_no_cross_silo_deletions(
+    exemptions: Set[Tuple[Type[Model], Type[Model]]], app_name: str | None = None
+) -> None:
+    for model_class in iter_models(app_name):
         if not hasattr(model_class._meta, "silo_limit"):
             continue
         deletion_task: BaseDeletionTask = deletions.get(model=model_class, query={})