Refactor and test h5netcdf scalar reading

satpy/readers/netcdf_utils.py

@@ -379,14 +379,15 @@ def get_data_as_xarray(variable):
     try:
         attrs = variable.attrs
     except AttributeError:
+        # netCDF4 backend requires usage of __dict__ to get the attributes
         attrs = variable.__dict__
     try:
-        arr = xr.DataArray(
-            variable[:], dims=variable.dimensions, attrs=attrs, name=variable.name)
-    except ValueError:
+        data = variable[:]
+    except (ValueError, IndexError):
         # Handle scalars for h5netcdf backend
-        arr = xr.DataArray(
-            variable.__array__(), dims=variable.dimensions, attrs=attrs, name=variable.name)
+        data = variable.__array__()
+
+    arr = xr.DataArray(data, dims=variable.dimensions, attrs=attrs, name=variable.name)
 
     return arr
 

satpy/tests/reader_tests/test_netcdf_utils.py

@@ -315,12 +315,31 @@ def test_get_data_as_xarray_netcdf4(tmp_path):
     assert res.attrs == NC_ATTRS
 
 
+def test_get_data_as_xarray_scalar_netcdf4(tmp_path):
+    """Test getting scalar xr.DataArray from netcdf4 variable."""
+    import numpy as np
+
+    from satpy.readers.netcdf_utils import get_data_as_xarray
+
+    data = 1
+    fname = tmp_path / "test.nc"
+    dset = _write_test_netcdf4(fname, data)
+
+    res = get_data_as_xarray(dset["test_data"])
+    np.testing.assert_equal(res.data, np.array(data))
+    assert res.attrs == NC_ATTRS
+
+
 def _write_test_netcdf4(fname, data):
     import netCDF4 as nc
 
     dset = nc.Dataset(fname, "w")
-    dset.createDimension("y", None)
-    var = dset.createVariable("test_data", "uint8", ("y",))
+    try:
+        dset.createDimension("y", data.size)
+        dims = ("y",)
+    except AttributeError:
+        dims = ()
+    var = dset.createVariable("test_data", "uint8", dims)
     var[:] = data
     var.setncatts(NC_ATTRS)
     # Turn off automatic scale factor and offset handling
@@ -348,10 +367,28 @@ def _write_test_h5netcdf(fname, data):
     import h5netcdf
 
     fid = h5netcdf.File(fname, "w")
-    fid.dimensions = {"y": data.size}
-    var = fid.create_variable("test_data", ("y",), "uint8")
-    var[:] = data
+    try:
+        fid.dimensions = {"y": data.size}
+        dims = ("y",)
+    except AttributeError:
+        dims = ()
+    var = fid.create_variable("test_data", dims, "uint8", data=data)
     for key in NC_ATTRS:
         var.attrs[key] = NC_ATTRS[key]
 
     return fid
+
+
+def test_get_data_as_xarray_scalar_h5netcdf(tmp_path):
+    """Test getting xr.DataArray from h5netcdf variable."""
+    import numpy as np
+
+    from satpy.readers.netcdf_utils import get_data_as_xarray
+
+    data = 1
+    fname = tmp_path / "test.nc"
+    fid = _write_test_h5netcdf(fname, data)
+
+    res = get_data_as_xarray(fid["test_data"])
+    np.testing.assert_equal(res.data, np.array(data))
+    assert res.attrs == NC_ATTRS