Fix store creation

Author: dstansby

numcodecs/tests/test_zarr3.py

@@ -36,7 +36,7 @@
 
 @pytest.fixture
 def store() -> StorePath:
-    return StorePath(MemoryStore(mode="w"))
+    return StorePath(MemoryStore(read_only=False))
 
 
 ALL_CODECS = [getattr(numcodecs.zarr3, cls_name) for cls_name in numcodecs.zarr3.__all__]