diff --git a/odc/loader/test_memreader.py b/odc/loader/test_memreader.py
index b769ec4..f336210 100644
--- a/odc/loader/test_memreader.py
+++ b/odc/loader/test_memreader.py
@@ -170,8 +170,8 @@ def test_memreader_zarr(sample_ds: xr.Dataset):
     gbox = sample_ds.odc.geobox
     chunks = None
 
-    md_store = {}
-    chunk_store = {}
+    md_store: dict[str, bytes] = {}
+    chunk_store: dict[str, bytes] = {}
     sample_ds.to_zarr(md_store, chunk_store, compute=False, consolidated=True)
 
     assert ".zmetadata" in md_store
diff --git a/odc/loader/testing/mem_reader.py b/odc/loader/testing/mem_reader.py
index 3f60c83..6b294fb 100644
--- a/odc/loader/testing/mem_reader.py
+++ b/odc/loader/testing/mem_reader.py
@@ -191,11 +191,12 @@ def _resolve_data_array(self) -> xr.DataArray:
             return self._xx
 
         assert self._spec is not None
-        kw = {
-            "target": self._src.uri,
-            "chunks": self._ctx.chunks,
-        }
-        src_ds = _from_zarr_spec(self._spec, regen_coords=True, **kw)
+        src_ds = _from_zarr_spec(
+            self._spec,
+            regen_coords=True,
+            target=self._src.uri,
+            chunks=self._ctx.chunks,
+        )
 
         if src_ds is None:
             raise ValueError("Failed to interpret driver data")