check that the store backend entrypoint does not create default indexes

pydata · dcherian · Jul 8, 2025 · Aug 7, 2023 · Aug 7, 2023 · Nov 13, 2023
commit 294b2f712425ca9424a4d6ad62912d653087beb5
diff --git a/xarray/tests/test_backends.py b/xarray/tests/test_backends.py
@@ -55,6 +55,7 @@
 from xarray.coding.variables import SerializationWarning
 from xarray.conventions import encode_dataset_coordinates
 from xarray.core import indexing
+from xarray.core.indexes import PandasIndex
 from xarray.core.options import set_options
 from xarray.core.utils import module_available
 from xarray.namedarray.pycompat import array_type
@@ -2050,6 +2051,26 @@ def test_encoding_enum__error_multiple_variable_with_changing_enum(self):
                         with self.roundtrip(original):
                             pass
 
+    @pytest.mark.parametrize("create_default_indexes", [True, False])
+    def test_create_default_indexes(self, tmp_path, create_default_indexes) -> None:
+        store_path = tmp_path / "tmp.nc"
+        original_ds = xr.Dataset(
+            {"data": ("x", np.arange(3))}, coords={"x": [-1, 0, 1]}
+        )
+        original_ds.to_netcdf(store_path, engine=self.engine, mode="w")
+
+        with open_dataset(
+            store_path,
+            engine=self.engine,
+            create_default_indexes=create_default_indexes,
+        ) as loaded_ds:
+            if create_default_indexes:
+                assert list(loaded_ds.xindexes) == ["x"] and isinstance(
+                    loaded_ds.xindexes["x"], PandasIndex
+                )
+            else:
+                assert len(loaded_ds.xindexes) == 0
+
 
 @requires_netCDF4
 class TestNetCDF4Data(NetCDF4Base):
@@ -4009,6 +4030,26 @@ def test_pickle(self) -> None:
     def test_pickle_dataarray(self) -> None:
         pass
 
+    @pytest.mark.parametrize("create_default_indexes", [True, False])
+    def test_create_default_indexes(self, tmp_path, create_default_indexes) -> None:
+        store_path = tmp_path / "tmp.nc"
+        original_ds = xr.Dataset(
+            {"data": ("x", np.arange(3))}, coords={"x": [-1, 0, 1]}
+        )
+        original_ds.to_netcdf(store_path, engine=self.engine, mode="w")
+
+        with open_dataset(
+            store_path,
+            engine=self.engine,
+            create_default_indexes=create_default_indexes,
+        ) as loaded_ds:
+            if create_default_indexes:
+                assert list(loaded_ds.xindexes) == ["x"] and isinstance(
+                    loaded_ds.xindexes["x"], PandasIndex
+                )
+            else:
+                assert len(loaded_ds.xindexes) == 0
+
 
 @requires_scipy
 class TestScipyFilePath(CFEncodedBase, NetCDF3Only):
@@ -6378,6 +6419,26 @@ def test_zarr_closing_internal_zip_store():
         assert_identical(original_da, loaded_da)
 
 
+@requires_zarr
+@pytest.mark.parametrize("create_default_indexes", [True, False])
+def test_zarr_create_default_indexes(tmp_path, create_default_indexes) -> None:
+    from xarray.core.indexes import PandasIndex
+
+    store_path = tmp_path / "tmp.zarr"
+    original_ds = xr.Dataset({"data": ("x", np.arange(3))}, coords={"x": [-1, 0, 1]})
+    original_ds.to_zarr(store_path, mode="w")
+
+    with open_dataset(
+        store_path, engine="zarr", create_default_indexes=create_default_indexes
+    ) as loaded_ds:
+        if create_default_indexes:
+            assert list(loaded_ds.xindexes) == ["x"] and isinstance(
+                loaded_ds.xindexes["x"], PandasIndex
+            )
+        else:
+            assert len(loaded_ds.xindexes) == 0
+
+
 @requires_zarr
 @pytest.mark.usefixtures("default_zarr_format")
 def test_raises_key_error_on_invalid_zarr_store(tmp_path):

diff --git a/xarray/tests/test_backends_api.py b/xarray/tests/test_backends_api.py
@@ -218,7 +218,7 @@ def test_default_indexes(self, create_default_indexes):
         if create_default_indexes:
             assert all(name in final.xindexes for name in ["x", "y"])
         else:
-            assert not final.xindexes
+            assert len(final.xindexes) == 0
 
     @pytest.mark.parametrize("create_default_indexes", [True, False])
     def test_default_indexes_passthrough(self, create_default_indexes):