Make iris-grib optional for tests.

Author: pp-mo

lib/iris/tests/integration/netcdf/test_load_managed_attributes.py

@@ -7,11 +7,15 @@
 # Annoyingly, this import is *not* redundant, as pytest import fails without it.
 import warnings
 
-import iris_grib  # noqa: F401
-from iris_grib.grib_phenom_translation._gribcode import (
-    GenericConcreteGRIBCode,
-    GRIBCode,
-)
+try:
+    import iris_grib  # noqa: F401
+    from iris_grib.grib_phenom_translation._gribcode import (
+        GenericConcreteGRIBCode,
+        GRIBCode,
+    )
+except ImportError:
+    iris_grib = None
+
 import numpy as np
 import pytest
 
@@ -178,6 +182,7 @@ def test_tuple_value__fail(self):
         assert result == ("[2", "3", "7]")
 
 
+@pytest.mark.skipif(iris_grib is None, reason="iris_grib is not available")
 class TestGribParam(LoadTestCommon):
     def _check_load(self, value):
         return self._check_load_inner("GRIB_PARAM", "GRIB_PARAM", value)

lib/iris/tests/integration/netcdf/test_save_managed_attributes.py

@@ -4,9 +4,12 @@
 # See LICENSE in the root of the repository for full licensing details.
 """Integration tests for netcdf saving of attributes with "special" handling."""
 
-# Unfortunately not redundant since pytest fails to import iris_grib without it.
-import iris_grib  # noqa: F401
-from iris_grib.grib_phenom_translation._gribcode import GRIBCode
+try:
+    import iris_grib
+    from iris_grib.grib_phenom_translation._gribcode import GRIBCode
+except ImportError:
+    iris_grib = None
+
 import pytest
 
 import iris
@@ -127,6 +130,7 @@ def test_none_object(self):
         assert result == "None"
 
 
+@pytest.mark.skipif(iris_grib is None, reason="iris_grib is not available")
 class TestGribParam(SaveTestCommon):
     def _check_save(self, value):
         return self._check_save_inner("GRIB_PARAM", "GRIB_PARAM", value)

lib/iris/tests/unit/fileformats/netcdf/attribute_handlers/test_GribParamHandler.py

@@ -4,14 +4,14 @@
 # See LICENSE in the root of the repository for full licensing details.
 """Unit tests for :class:`iris.fileformats.netcdf._attribute_handlers.StashHandler`."""
 
-# Unfortunately not redundant since pytest fails to import iris_grib without it.
-import iris_grib  # noqa: F401
+import pytest
+
+iris_grib = pytest.importorskip("iris_grib")
 from iris_grib.grib_phenom_translation._gribcode import (
     GenericConcreteGRIBCode,
     GRIBCode,
 )
 import numpy as np
-import pytest
 
 from iris.fileformats.netcdf._attribute_handlers import ATTRIBUTE_HANDLERS