Update test to store a BSON confirmation date; fix case model to dese…

…rialise such dates #2714

I chose not to handle this in the mongo_store because it would have been (cognitively and computationally) inefficient: it would mean dumping the BSON, loading the JSON, patching it, dumping that, then loading in the model. Nein, danke!

data-serving/reusable-data-service/reusable_data_service/model/case.py

@@ -30,15 +30,26 @@ def from_json(cls, obj: str) -> type:
     def from_dict(cls, dictionary: dict[str, Any]) -> type:
         case = cls()
         for key in dictionary:
-            if key in ["confirmation_date"]:
-                # parse as an ISO 8601 date
-                date_dt = datetime.datetime.strptime(
-                    dictionary[key], "%Y-%m-%dT%H:%M:%S.%fZ"
-                )
-                date = date_dt.date()
-                setattr(case, key, date)
+            if key in cls.date_fields():
+                # handle a few different ways dates get represented in dictionaries
+                maybe_date = dictionary[key]
+                if isinstance(maybe_date, datetime.datetime):
+                    value = maybe_date.date()
+                elif isinstance(maybe_date, datetime.date):
+                    value = maybe_date
+                elif isinstance(maybe_date, str):
+                    value = datetime.datetime.strptime(
+                        maybe_date, "%Y-%m-%dT%H:%M:%S.%fZ"
+                    )
+                elif isinstance(maybe_date, dict) and "$date" in maybe_date:
+                    value = datetime.datetime.strptime(
+                        maybe_date["$date"], "%Y-%m-%dT%H:%M:%SZ"
+                    ).date()
+                else:
+                    raise ValueError(f"Cannot interpret date {maybe_date}")
             else:
-                setattr(case, key, dictionary[key])
+                value = dictionary[key]
+            setattr(case, key, value)
         case.validate()
         return case
 
@@ -49,6 +60,12 @@ def validate(self):
         elif self.confirmation_date is None:
             raise ValueError("Confirmation Date must have a value")
 
+    @classmethod
+    def date_fields(cls) -> list[str]:
+        """Record where dates are kept because they sometimes need special treatment.
+        A subclass could override this method to indicate it stores additional date fields."""
+        return ["confirmation_date"]
+
 
 # Actually we want to capture extra fields which can be specified dynamically:
 # so Case is the class that you should use.

data-serving/reusable-data-service/tests/test_case_end_to_end.py

@@ -2,6 +2,8 @@
 import mongomock
 import pymongo
 
+from datetime import datetime
+
 from reusable_data_service import app, set_up_controllers
 
 
@@ -31,7 +33,7 @@ def test_get_case_with_known_id(client_with_patched_mongo):
     db = pymongo.MongoClient("mongodb://localhost:27017/outbreak")
     case_id = (
         db["outbreak"]["cases"]
-        .insert_one({"confirmation_date": "2021-12-31T01:23:45.678Z"})
+        .insert_one({"confirmation_date": datetime(2021, 12, 31, 1, 23, 45, 678)})
         .inserted_id
     )
     response = client_with_patched_mongo.get(f"/api/cases/{str(case_id)}")