Fix properties test

Author: dstansby

src/zarr/testing/strategies.py

@@ -356,7 +356,12 @@ def basic_indices(
         allow_newaxis=allow_newaxis,
         allow_ellipsis=allow_ellipsis,
     ).filter(
-        lambda idxr: (not (is_negative_slice(idxr) or any(is_negative_slice(idx) for idx in idxr)))
+        lambda idxr: (
+            not (
+                is_negative_slice(idxr)
+                or (isinstance(idxr, tuple) and any(is_negative_slice(idx) for idx in idxr))
+            )
+        )
     )
     if math.prod(shape) >= 3:
         strategy = end_slices(shape=shape) | strategy