Granularity for fixed surface arguments

iris_grib/_load_convert.py

@@ -1,4 +1,4 @@
-# (C) British Crown Copyright 2014 - 2018, Met Office
+# (C) British Crown Copyright 2014 - 2019, Met Office
 #
 # This file is part of iris-grib.
 #
@@ -2354,6 +2354,7 @@ def product_definition_section(section, metadata, discipline, tablesVersion,
     template = section['productDefinitionTemplateNumber']
 
     probability = None
+    includes_fixed_surface_keys = True
     if template == 0:
         # Process analysis or forecast at a horizontal level or
         # in a horizontal layer at a point in time.
@@ -2377,8 +2378,10 @@ def product_definition_section(section, metadata, discipline, tablesVersion,
         product_definition_template_15(section, metadata, rt_coord)
     elif template == 31:
         # Process satellite product.
+        includes_fixed_surface_keys = False
         product_definition_template_31(section, metadata, rt_coord)
     elif template == 32:
+        includes_fixed_surface_keys = False
         product_definition_template_32(section, metadata, rt_coord)
     elif template == 40:
         product_definition_template_40(section, metadata, rt_coord)
@@ -2389,13 +2392,27 @@ def product_definition_section(section, metadata, discipline, tablesVersion,
 
     # Translate GRIB2 phenomenon to CF phenomenon.
     if tablesVersion != _CODE_TABLES_MISSING:
-        translate_phenomenon(metadata, discipline,
-                             section['parameterCategory'],
-                             section['parameterNumber'],
-                             section['typeOfFirstFixedSurface'],
-                             section['scaledValueOfFirstFixedSurface'],
-                             section['typeOfSecondFixedSurface'],
-                             probability=probability)
+        translation_kwargs = {
+            'metadata': metadata,
+            'discipline': discipline,
+            'parameterCategory': section['parameterCategory'],
+            'parameterNumber': section['parameterNumber'],
+            'probability': probability
+        }
+
+        # Won't always be able to populate the below arguments -
+        # missing from some template definitions.
+        fixed_surface_keys = [
+            'typeOfFirstFixedSurface',
+            'scaledValueOfFirstFixedSurface',
+            'typeOfSecondFixedSurface'
+        ]
+
+        for section_key in fixed_surface_keys:
+            translation_kwargs[section_key] = \
+                section[section_key] if includes_fixed_surface_keys else None
+
+        translate_phenomenon(**translation_kwargs)
 
 
 ###############################################################################

iris_grib/tests/unit/load_convert/test_product_definition_section.py

@@ -0,0 +1,138 @@
+# (C) British Crown Copyright 2014 - 2019, Met Office
+#
+# This file is part of iris-grib.
+#
+# iris-grib is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Lesser General Public License as published by the
+# Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# iris-grib is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with iris-grib.  If not, see <http://www.gnu.org/licenses/>.
+"""
+Tests for `iris_grib._load_convert.product_definition_section`.
+
+"""
+
+from __future__ import (absolute_import, division, print_function)
+
+# import iris_grib.tests first so that some things can be initialised
+# before importing anything else.
+import iris_grib.tests as tests
+
+from iris.coords import DimCoord
+import mock
+import six
+
+from itertools import product
+
+from iris_grib._load_convert import product_definition_section
+from iris_grib.tests.unit.load_convert import empty_metadata
+from iris_grib.tests.unit.load_convert.test_product_definition_template_0 \
+    import section_4 as pdt_0_section_4
+from iris_grib.tests.unit.load_convert.test_product_definition_template_31 \
+    import section_4 as pdt_31_section_4
+
+
+class TestFixedSurfaces(tests.IrisGribTest):
+    """
+    Tests focussing on the handling of fixed surface elements in section 4.
+    Expects/ignores depending on the template number.
+    """
+    def setUp(self):
+        self.patch('warnings.warn')
+        self.translate_phenomenon_patch = self.patch(
+            'iris_grib._load_convert.translate_phenomenon'
+        )
+
+        # Prep placeholder variables for product_definition_section.
+        self.discipline = mock.sentinel.discipline
+        self.tablesVersion = mock.sentinel.tablesVersion
+        self.rt_coord = DimCoord(24, 'forecast_reference_time',
+                                 units='hours since epoch')
+        self.metadata = empty_metadata()
+
+        self.templates = {0: pdt_0_section_4(), 31: pdt_31_section_4()}
+        self.fixed_surface_keys = [
+            'typeOfFirstFixedSurface',
+            'scaledValueOfFirstFixedSurface',
+            'typeOfSecondFixedSurface'
+        ]
+
+    def _check_fixed_surface(self, fs_is_expected, fs_is_present):
+        """
+        Whether or not fixed surface elements are expected/present in the
+        section 4 keys, most of the code is shared so we are using a single
+        function with parameters.
+        """
+
+        # Use the section 4 from either product_definition_section #1 or #31.
+        # #0 contains fixed surface elements, #31 does not.
+        template_number = 0 if fs_is_expected else 31
+        section_4 = self.templates[template_number]
+        section_4.update({
+            'productDefinitionTemplateNumber': template_number,
+            'parameterCategory': None,
+            'parameterNumber': None
+        })
+
+        for key in self.fixed_surface_keys:
+            # Force the presence or absence of the fixed surface elements even
+            # when they're respectively ignored or expected.
+            if fs_is_present and key not in section_4:
+                section_4[key] = pdt_0_section_4()[key]
+            elif (not fs_is_present) and key in section_4:
+                del section_4[key]
+
+        def run_function():
+            # For re-use in every type of test below.
+            product_definition_section(
+                section_4, self.metadata, self.discipline, self.tablesVersion,
+                self.rt_coord)
+
+        if fs_is_expected and not fs_is_present:
+            # Should error since the expected keys are missing.
+            error_message = 'FixedSurface'
+            with six.assertRaisesRegex(self, KeyError, error_message):
+                run_function()
+        else:
+            # Should have a successful run for all other circumstances.
+
+            # Translate_phenomenon_patch is the end of the function,
+            # and should be able to accept None for the fixed surface
+            # arguments. So should always have run.
+            previous_call_count = self.translate_phenomenon_patch.call_count
+            run_function()
+            self.assertEqual(self.translate_phenomenon_patch.call_count,
+                             previous_call_count + 1)
+            phenom_call_args = self.translate_phenomenon_patch.call_args[1]
+            for key in self.fixed_surface_keys:
+                # Check whether None or actual values have been passed for
+                # the fixed surface arguments.
+                if fs_is_expected:
+                    self.assertEqual(phenom_call_args[key], section_4[key])
+                else:
+                    self.assertIsNone(phenom_call_args[key])
+
+    def test_all_combinations(self):
+        """
+        Test all combinations of fixed surface being expected/present
+
+        a. Expected and Present - standard behaviour for most templates
+        b. Expected and Absent - unplanned combination, should error
+        c. Unexpected and Present - unplanned combination, should be handled
+            identically to (d)
+        d. Unexpected and Absent - standard behaviour for a few templates
+            e.g. #31
+        """
+        for pair in product([True, False], repeat=2):
+            self._check_fixed_surface(*pair)
+
+
+if __name__ == '__main__':
+    tests.main()

iris_grib/tests/unit/load_convert/test_product_definition_template_31.py

@@ -1,4 +1,4 @@
-# (C) British Crown Copyright 2014 - 2017, Met Office
+# (C) British Crown Copyright 2014 - 2019, Met Office
 #
 # This file is part of iris-grib.
 #
@@ -37,6 +37,19 @@
 from iris_grib._load_convert import product_definition_template_31
 
 
+def section_4():
+    # Also needed for test_product_definition_section.py.
+    series = mock.sentinel.satelliteSeries
+    number = mock.sentinel.satelliteNumber
+    instrument = mock.sentinel.instrumentType
+    return {'NB': 1,
+            'satelliteSeries': series,
+            'satelliteNumber': number,
+            'instrumentType': instrument,
+            'scaleFactorOfCentralWaveNumber': 1,
+            'scaledValueOfCentralWaveNumber': 12}
+
+
 class Test(tests.IrisGribTest):
     def setUp(self):
         self.patch('warnings.warn')
@@ -47,16 +60,8 @@ def setUp(self):
 
     def test(self):
         # Prepare the arguments.
-        series = mock.sentinel.satelliteSeries
-        number = mock.sentinel.satelliteNumber
-        instrument = mock.sentinel.instrumentType
         rt_coord = mock.sentinel.observation_time
-        section = {'NB': 1,
-                   'satelliteSeries': series,
-                   'satelliteNumber': number,
-                   'instrumentType': instrument,
-                   'scaleFactorOfCentralWaveNumber': 1,
-                   'scaledValueOfCentralWaveNumber': 12}
+        section = section_4()
 
         # Call the function.
         metadata = empty_metadata()