correct test invocations and weaken the requirements for crc32c json

Author: d-v-b

src/zarr/codecs/crc32c_.py

@@ -2,7 +2,7 @@
 
 from collections.abc import Mapping
 from dataclasses import dataclass
-from typing import TYPE_CHECKING, Literal, TypedDict, TypeGuard, cast, overload
+from typing import TYPE_CHECKING, Literal, NotRequired, TypedDict, TypeGuard, cast, overload
 
 import numpy as np
 import typing_extensions
@@ -21,7 +21,7 @@
 
 
 class Crc32cConfig_V2(TypedDict):
-    location: ReadOnly[Literal["start", "end"]]
+    location: NotRequired[ReadOnly[Literal["start", "end"]]]
 
 
 class Crc32cConfig_V3(TypedDict): ...
@@ -37,9 +37,9 @@ class Crc32cJSON_V3(NamedConfig[Literal["crc32c"], Crc32cConfig_V3]): ...
 def check_json_v2(data: object) -> TypeGuard[Crc32cJSON_V2]:
     return (
         isinstance(data, Mapping)
-        and set(data.keys()) == {"id", "location"}
+        and "id" in data
         and data["id"] == "crc32c"
-        and data["location"] in ("start", "end")
+        and data.get("location", "end") in ("start", "end")
     )
 
 
@@ -64,7 +64,7 @@ def from_dict(cls, data: dict[str, JSON]) -> Self:
     @classmethod
     def _from_json_v2(cls, data: CodecJSON) -> Self:
         if check_json_v2(data):
-            if data["location"] != "end":
+            if data.get("location", "end") != "end":
                 raise ValueError('The crc32c codec only supports the "end" location')
             return cls()
         msg = (

tests/test_codecs/test_crc32c.py

@@ -69,8 +69,6 @@ def test_from_json_v2_valid(self) -> None:
         "invalid_data",
         [
             {"id": "wrong_codec"},  # Wrong codec name
-            {"name": "crc32c"},  # V3 format in V2 method
-            {"id": "crc32c", "extra": "field"},  # Extra fields
             {},  # Missing id
             {"other": "field"},  # Wrong field name
         ],
@@ -138,7 +136,6 @@ def test_check_json_v2_valid(self, valid_data: Crc32cJSON_V2) -> None:
         [
             {"id": "wrong_codec"},
             {"name": "crc32c"},
-            {"id": "crc32c", "extra": "field"},
             {},
             "not_a_dict",
             None,