Review fixes

Author: Will Benfold

lib/iris/__init__.py

@@ -151,12 +151,14 @@ def __init__(self, datum_support=False):
         .. note::
 
             iris.FUTURE.example_future_flag does not exist. It is provided
-            as an example because there are currently no flags in
-            iris.Future.
+            as an example.
 
         """
-        # The flag 'example_future_flag' is provided as a future reference
-        # for the structure of this class.
+        # The flag 'example_future_flag' is provided as a reference for the
+        # structure of this class.
+        #
+        # Note that self.__dict__ is used explicitly due to the manner in which
+        # __setattr__ is overridden.
         #
         # self.__dict__['example_future_flag'] = example_future_flag
         self.__dict__["datum_support"] = datum_support
@@ -211,8 +213,7 @@ def context(self, **kwargs):
         .. note::
 
             iris.FUTURE.example_future_flag does not exist and is
-            provided only as an example since there are currently no
-            flags in Future.
+            provided only as an example.
 
         """
         # Save the current context

lib/iris/coord_systems.py

@@ -238,6 +238,7 @@ def _pretty_attrs(self):
                     self.longitude_of_prime_meridian,
                 )
             )
+        # An unknown crs datum will be treated as None
         if self.datum is not None and self.datum != "unknown":
             attrs.append(
                 (
@@ -302,6 +303,7 @@ def __getattr__(self, name):
             return self._crs.ellipsoid.inverse_flattening
         if name == "datum":
             datum = self._crs.datum.name
+            # An unknown crs datum will be treated as None
             if datum == "unknown":
                 return None
             return datum

lib/iris/fileformats/_nc_load_rules/helpers.py

@@ -264,6 +264,7 @@ def _get_ellipsoid(cf_grid_var):
             if proj_crs.datum is not None:
                 datum = proj_crs.datum.name
 
+    # An unknown crs datum will be treated as None
     if datum == "unknown":
         datum = None
 

lib/iris/tests/integration/test_Datums.py

@@ -0,0 +1,53 @@
+# Copyright Iris contributors
+#
+# This file is part of Iris and is released under the LGPL license.
+# See COPYING and COPYING.LESSER in the root of the repository for full
+# licensing details.
+"""Integration tests for :class:`iris.coord_systems` datum suppport."""
+
+# Import iris.tests first so that some things can be initialised before
+# importing anything else.
+import iris.tests as tests  # isort:skip
+
+import cartopy.crs as ccrs
+import numpy as np
+
+from iris.coord_systems import GeogCS, LambertConformal
+
+
+class TestDatumTransformation(tests.IrisTest):
+    def setUp(self):
+        self.x_points = np.array([-1.5])
+        self.y_points = np.array([50.5])
+
+        self.start_crs = ccrs.OSGB(False)
+
+    def test_transform_points_datum(self):
+
+        # Iris version
+        wgs84 = GeogCS.from_datum("WGS84")
+        iris_cs = LambertConformal(
+            central_lat=54,
+            central_lon=-4,
+            secant_latitudes=[52, 56],
+            ellipsoid=wgs84,
+        )
+        iris_cs_as_cartopy = iris_cs.as_cartopy_crs()
+
+        # Cartopy equivalent
+        cartopy_cs = ccrs.LambertConformal(
+            central_latitude=54,
+            central_longitude=-4,
+            standard_parallels=[52, 56],
+            globe=ccrs.Globe("WGS84"),
+        )
+
+        expected = cartopy_cs.transform_points(
+            self.start_crs, self.x_points, self.y_points
+        )
+
+        actual = iris_cs_as_cartopy.transform_points(
+            self.start_crs, self.x_points, self.y_points
+        )
+
+        self.assertArrayEqual(expected, actual)

lib/iris/tests/test_coordsystem.py

@@ -498,7 +498,7 @@ def test_south_cutoff(self):
 
 class Test_Datums(tests.IrisTest):
     def test_default_none(self):
-        cs = GeogCS(6543210, 6500000)
+        cs = GeogCS(6543210, 6500000)  # Arbitrary radii
         cartopy_crs = cs.as_cartopy_crs()
         self.assertStringEqual(cartopy_crs.datum.name, "unknown")
 

lib/iris/tests/unit/coord_systems/test_LambertConformal.py

@@ -9,10 +9,7 @@
 # importing anything else.
 import iris.tests as tests  # isort:skip
 
-import cartopy.crs as ccrs
-import numpy as np
-
-from iris.coord_systems import GeogCS, LambertConformal
+from iris.coord_systems import LambertConformal
 
 
 class Test_init_defaults(tests.IrisTest):
@@ -77,43 +74,5 @@ def test_optional_args_None(self):
         self._check_crs_defaults(crs)
 
 
-class TestDatumTransformation(tests.IrisTest):
-    def setUp(self):
-        self.x_points = np.array([-1.5])
-        self.y_points = np.array([50.5])
-
-        self.start_crs = ccrs.OSGB(False)
-
-    def test_transform_points_datum(self):
-
-        # Iris version
-        wgs84 = GeogCS.from_datum("WGS84")
-        iris_cs = LambertConformal(
-            central_lat=54,
-            central_lon=-4,
-            secant_latitudes=[52, 56],
-            ellipsoid=wgs84,
-        )
-        iris_cs_as_cartopy = iris_cs.as_cartopy_crs()
-
-        # Cartopy equivalent
-        cartopy_cs = ccrs.LambertConformal(
-            central_latitude=54,
-            central_longitude=-4,
-            standard_parallels=[52, 56],
-            globe=ccrs.Globe("WGS84"),
-        )
-
-        expected = cartopy_cs.transform_points(
-            self.start_crs, self.x_points, self.y_points
-        )
-
-        actual = iris_cs_as_cartopy.transform_points(
-            self.start_crs, self.x_points, self.y_points
-        )
-
-        self.assertArrayEqual(expected, actual)
-
-
 if __name__ == "__main__":
     tests.main()