Add tests for roi (#115)

* Add tests for roi

* Add load

* Add close

* Acheck something

* back

docs/whats-new.rst

@@ -12,12 +12,16 @@ Enhancements
 ~~~~~~~~~~~~
 
 - new :py:func:`~Grid.extent_as_polygon` method, which creates a polygon
-  drawing the contours of a Grid.
+  outlining the contours of a Grid.
 
 
 Bug fixes
 ~~~~~~~~~
 
+- the xarray accessor method ``roi()`` now preserves encoding (:issue:`109`).
+  By `Johannes Landmann <https://github.com/jlandmann>`_
+
+
 
 v0.2.2 (21 June 2018)
 ---------------------

salem/sio.py

@@ -512,15 +512,15 @@ def roi(self, ds=None, **kwargs):
         out.attrs = self._obj.attrs
         out.encoding = self._obj.encoding
         if isinstance(out, xr.Dataset):
-            for v in self._obj.variables.keys():
+            for v in self._obj.variables:
                 out[v].encoding = self._obj[v].encoding
         if isinstance(out, xr.DataArray):
             out.name = self._obj.name
 
         # add pyproj string everywhere
         out.attrs['pyproj_srs'] = self.grid.proj.srs
         if isinstance(out, xr.Dataset):
-            for v in out.variables:
+            for v in out.data_vars:
                 out.variables[v].attrs = self._obj.variables[v].attrs
                 out.variables[v].attrs['pyproj_srs'] = self.grid.proj.srs
         return out

salem/tests/test_misc.py

@@ -526,6 +526,18 @@ def test_era(self):
 
         np.testing.assert_almost_equal(dss.longitude, [90.0, 90.75, 91.5])
 
+    @requires_xarray
+    def test_roi(self):
+        import xarray as xr
+        # Check that all attrs are preserved
+        with sio.open_xr_dataset(get_demo_file('era_interim_tibet.nc')) as ds:
+            ds.encoding = {'_FillValue': np.NaN}
+            ds['t2m'].encoding = {'_FillValue': np.NaN}
+            ds_ = ds.salem.roi(roi=np.ones_like(ds.t2m.values[0, ...]))
+            xr.testing.assert_identical(ds, ds_)
+            assert ds.encoding == ds_.encoding
+            assert ds.t2m.encoding == ds_.t2m.encoding
+
     @requires_xarray
     @requires_geopandas  # because of the grid tests, more robust with GDAL
     def test_basic_wrf(self):