Add failing test for format_lat dropping attrs

Author: maresb

tests/test_utils.py

@@ -0,0 +1,29 @@
+import numpy as np
+import xarray as xr
+
+from xarray_regrid.utils import format_lat
+
+
+def test_format_lat():
+    lat_vals = np.arange(-89.5, 89.5 + 1, 1)
+    lon_vals = np.arange(-179.5, 179.5 + 1, 1)
+    x_vals = np.broadcast_to(lat_vals, (len(lon_vals), len(lat_vals)))
+    ds = xr.Dataset(
+        data_vars={"x": (("lon", "lat"), x_vals)},
+        coords={"lat": lat_vals, "lon": lon_vals},
+        attrs={"foo": "bar"},
+    )
+    ds.lat.attrs["is"] = "coord"
+    ds.x.attrs["is"] = "data"
+
+    formatted = format_lat(ds, ds, {"lat": "lat", "lon": "lon"})
+    # Check that lat has been extended to include poles
+    assert formatted.lat.values[0] == -90
+    assert formatted.lat.values[-1] == 90
+    # Check that data has been extrapolated to include poles
+    assert (formatted.x.isel(lat=0) == -89.5).all()
+    assert (formatted.x.isel(lat=-1) == 89.5).all()
+    # Check that attrs have been preserved
+    assert formatted.attrs["foo"] == "bar"
+    assert formatted.lat.attrs["is"] == "coord"
+    assert formatted.x.attrs["is"] == "data"