Add tests for more intelligible errors.

lib/iris/experimental/ugrid/load.py

@@ -490,7 +490,7 @@ def _build_mesh_coords(mesh, cf_var):
  # We should probably issue warnings and recover, but that is too much
  # work. Raising a more intelligible error is easy to do though.
  msg = (
- f"mesh data variable {cf_var.name!s} has an invalid "
+ f"mesh data variable {cf_var.name!r} has an invalid "
  f"location={location!r}."
  )
  raise ValueError(msg)

lib/iris/tests/unit/experimental/ugrid/load/test_load_meshes.py

@@ -27,50 +27,58 @@ def tearDownModule():
  rmtree(TMP_DIR)
 
 
-def cdl_to_nc(cdl):
- cdl_path = str(TMP_DIR / "tst.cdl")
- nc_path = str(TMP_DIR / f"{uuid4()}.nc")
+def cdl_to_nc(cdl, tmpdir=None):
+ if tmpdir is None:
+ tmpdir = TMP_DIR
+ cdl_path = str(tmpdir / "tst.cdl")
+ nc_path = str(tmpdir / f"{uuid4()}.nc")
  # Use ncgen to convert this into an actual (temporary) netCDF file.
  ncgen_from_cdl(cdl_str=cdl, cdl_path=cdl_path, nc_path=nc_path)
  return nc_path
 
 
-class TestsBasic(tests.IrisTest):
+_TEST_CDL_HEAD = """
+netcdf mesh_test {
+ dimensions:
+ node = 3 ;
+ face = 1 ;
+ vertex = 3 ;
+ levels = 2 ;
+ variables:
+ int mesh ;
+ mesh:cf_role = "mesh_topology" ;
+ mesh:topology_dimension = 2 ;
+ mesh:node_coordinates = "node_x node_y" ;
+ mesh:face_node_connectivity = "face_nodes" ;
+ float node_x(node) ;
+ node_x:standard_name = "longitude" ;
+ float node_y(node) ;
+ node_y:standard_name = "latitude" ;
+ int face_nodes(face, vertex) ;
+ face_nodes:cf_role = "face_node_connectivity" ;
+ face_nodes:start_index = 0 ;
+ int levels(levels) ;
+ float node_data(levels, node) ;
+ node_data:coordinates = "node_x node_y" ;
+ node_data:location = "node" ;
+ node_data:mesh = "mesh" ;
+"""
+
+_TEST_CDL_TAIL = """
+data:
+ mesh = 0;
+ node_x = 0., 2., 1.;
+ node_y = 0., 0., 1.;
+ face_nodes = 0, 1, 2;
+ levels = 1, 2;
+ node_data = 0., 0., 0.;
+ }
+"""
+
+
+class TestLoadErrors(tests.IrisTest):
  def setUp(self):
- self.ref_cdl = """
- netcdf mesh_test {
- dimensions:
- node = 3 ;
- face = 1 ;
- vertex = 3 ;
- levels = 2 ;
- variables:
- int mesh ;
- mesh:cf_role = "mesh_topology" ;
- mesh:topology_dimension = 2 ;
- mesh:node_coordinates = "node_x node_y" ;
- mesh:face_node_connectivity = "face_nodes" ;
- float node_x(node) ;
- node_x:standard_name = "longitude" ;
- float node_y(node) ;
- node_y:standard_name = "latitude" ;
- int face_nodes(face, vertex) ;
- face_nodes:cf_role = "face_node_connectivity" ;
- face_nodes:start_index = 0 ;
- int levels(levels) ;
- float node_data(levels, node) ;
- node_data:coordinates = "node_x node_y" ;
- node_data:location = "node" ;
- node_data:mesh = "mesh" ;
- data:
- mesh = 0;
- node_x = 0., 2., 1.;
- node_y = 0., 0., 1.;
- face_nodes = 0, 1, 2;
- levels = 1, 2;
- node_data = 0., 0., 0.;
- }
- """
+ self.ref_cdl = _TEST_CDL_HEAD + _TEST_CDL_TAIL
  self.nc_path = cdl_to_nc(self.ref_cdl)
 
  def add_second_mesh(self):

lib/iris/tests/unit/experimental/ugrid/load/test_meshload_checks.py

@@ -0,0 +1,77 @@
+import pytest
+
+import iris
+from iris.experimental.ugrid.load import PARSE_UGRID_ON_LOAD
+
+from .test_load_meshes import (
+ _TEST_CDL_HEAD,
+ _TEST_CDL_TAIL,
+ cdl_to_nc,
+)
+
+
+class TestMeshLoad:
+ def _create_testnc(self, location="node", meshdim="node"):
+ # Add an extra (possibly mal-formed) mesh data to the testfile.
+ if location is None:
+ location_cdl = ""
+ else:
+ location_cdl = f'extra_data:location = "{location}" ;'
+
+ extra_cdl = f"""
+ float extra_data(levels, {meshdim}) ;
+ extra_data:coordinates = "node_x node_y" ;
+ {location_cdl}
+ extra_data:mesh = "mesh" ;
+"""
+ # Insert this into the definitions part of the 'standard' testfile CDL
+ extended_cdl = _TEST_CDL_HEAD + extra_cdl + _TEST_CDL_TAIL
+ testfile_path = cdl_to_nc(extended_cdl, tmpdir=self.tmpdir)
+ return testfile_path
+
+ @pytest.fixture(params=["nolocation", "badlocation", "baddim"])
+ def failnc(self, request, tmp_path_factory):
+ self.param = request.param
+ kwargs = {}
+ if self.param == "nolocation":
+ kwargs["location"] = None
+ elif self.param == "badlocation":
+ kwargs["location"] = "invalid_location"
+ elif self.param == "baddim":
+ kwargs["meshdim"] = "vertex"
+ else:
+ raise ValueError(f"unexpected param: {self.param}")
+
+ self.tmpdir = tmp_path_factory.mktemp("meshload")
+ return self._create_testnc(**kwargs)
+
+ def test_extrameshvar__ok(self, tmp_path_factory):
+ # Check that the default cdl construction loads OK
+ self.tmpdir = tmp_path_factory.mktemp("meshload")
+ testnc = self._create_testnc()
+ with PARSE_UGRID_ON_LOAD.context():
+ iris.load(testnc)
+
+ def test_extrameshvar__fail(self, failnc):
+ # Check that the expected errors are raised in various cases.
+ param = self.param
+ if param == "nolocation":
+ match_msg = (
+ "mesh data variable 'extra_data' has an " "invalid location='<empty>'."
+ )
+ elif param == "badlocation":
+ match_msg = (
+ "mesh data variable 'extra_data' has an "
+ "invalid location='invalid_location'."
+ )
+ elif param == "baddim":
+ match_msg = (
+ "mesh data variable 'extra_data' does not have the node mesh "
+ "dimension 'node', in its dimensions."
+ )
+ else:
+ raise ValueError(f"unexpected param: {param}")
+
+ with PARSE_UGRID_ON_LOAD.context():
+ with pytest.raises(ValueError, match=match_msg):
+ iris.load(failnc)