OriginVisitStatus: Allow "created" status

Related to T2310

swh/model/hypothesis_strategies.py

@@ -177,7 +177,7 @@ def origin_visit_statuses_d():
         dict,
         visit=integers(1, 1000),
         origin=urls(),
-        status=sampled_from(["ongoing", "full", "partial"]),
+        status=sampled_from(["created", "ongoing", "full", "partial"]),
         date=aware_datetimes(),
         snapshot=optional(sha1_git()),
         metadata=optional(metadata_dicts()),

swh/model/model.py

@@ -263,7 +263,8 @@ class OriginVisitStatus(BaseModel):
 
     date = attr.ib(type=datetime.datetime, validator=type_validator())
     status = attr.ib(
-        type=str, validator=attr.validators.in_(["ongoing", "full", "partial"])
+        type=str,
+        validator=attr.validators.in_(["created", "ongoing", "full", "partial"]),
     )
     snapshot = attr.ib(type=Optional[Sha1Git], validator=type_validator())
     metadata = attr.ib(