166 fix unittests

[alasdair-roy]

Closes #166 #91

To be completed prior to review request and updated as required during the review process.

If the answer to an item on the list is not applicable, feel free to replace the checkbox with 'N/A' to give extra clarity.

All developers are reminded to follow the ancil working practices

---

Branch

Related branches (e.g. ancillary-file-science):

[please link any related branches here]

ANTS rose stem logs

[please enter the workflow name here as it has been run e.g. ants-trunk/run5]

ancillary-file-science rose stem logs

[please enter the workflow name here as it has been run e.g. ancillary-file-science/run1]

---

Testing

For core ANTS only tests, the bare minimum that will be accepted is the group=unittests but many, if not most, changes will need to test other groups to ensure they meet reviewer expectations. In general, it should be possible and is advised to run the group=all group prior to review submission as this will catch any consequential issues. Additionally you must run the ancillary-file-science tests, pointing at your branch, with group=all to capture any behaviour changes affecting Science codes.

If your change will alter existing science results, you will need to seek appropriate Scientific validation and confirm that the model has been initialised with your new development. Inspecting a change in xconv/pyplot/visualiser of choice is not sufficient to demonstrate the model can be initialised from your file.

---

Impact of change

• This will maintain results for ANTS cylc vip ./rose-stem -z group=all tests
• This will this maintain results for ancillary-file-science cylc vip ./rose-stem -z group=all tests
• If this change adds a new capability, evidence has been supplied to show testing of ancillary generation across different resolutions e.g. For global ancillary generation capabilities for use in NWP n1280e is expected to have been tested
• This change has significantly impacted required resources (runtime and memory) in existing ancillary generation (if yes, give details)
• This change alters existing ancils

Add further comments/details for your reviewers here on the impacts of the change......

---

Approvals for this change

• I have approval from the ANTS core development team for these changes

---

New functionality further testing

• If adding new functionality to existing codes, I confirm that the new code doesn't change results when it is switched off and ''works'' when switched on
• Unittests have been added
• Rose stem tests have been added for any new functionality
• If adding new functionality please confirm that the new code compares across different standard decompositions.
• I have not encountered any failures in my rose-stem output(s)
  These tasks must succeed for your ticket to pass review.
• I have remembered to run the code style check tasks/tools

Add details of any further testing here.

---

Other

• I have read the Contributor Licence Agreement
• I have added my name and affiliation to the Contributors list if I am not already on there in this PR.
• The issue labels, milestones, etc. are correct
• Links to all related issues have been provided in the pull request description
• I have requested a code reviewer
• Source data has been added or changed - please include a link to the license

I confirm that all code is my own and that my contributions are not subject to copyright or license restrictions (see Contributor Licence Agreement).	your name
I confirm I have not knowingly violated intellectual property rights (IPR) and have taken sensible measures to prevent doing so, including appropriate attribution for usage of Generative AI. I confirm that this work is my own, and I understand that it is my responsibility to ensure I am not violating others’ IPR. This includes taking reasonable steps to ensure that all tools used while creating this contribution did not infringe IPR.	your name

Please add any further notes here. If Generative AI tools have been used, a brief summary (e.g. "Github copilot used to add extra unittests") should be provided.

---

Rose stem logs

Please copy in the contents of your trac_status.log file(s) below (found in the cylc-run directory for your rose stem run) to your rose-stem testing here. Note: if your changes lead to a change in answers, you must run cylc vip ./rose-stem -z group=all to help ensure all affected configurations has been flagged up.

Wed 16 Sep 15:23:55 BST 2026 Git status: [ "" ] Commit: 9c11d1f

---

Test Results - Summary

tasks	total
failed	6
succeeded	63

Test Results - Detail

task	status
install_cold	succeeded
isort	succeeded
ancil_general_regrid_3d_to_3d_split2	succeeded
ancil_general_regrid_grid_to_grid_latitude_weighted_kdtree_split0	succeeded
ancil_2anc_split1	succeeded
ancil_2anc_split2	succeeded
ancil_general_regrid_with_time_constraint_spiral_split1	succeeded
ancil_general_regrid_grid_to_n48_namelist_split0	succeeded
ancil_general_regrid_with_time_constraint_kdtree_split1	succeeded
ancil_general_regrid_grid_to_grid_spiral_split1	succeeded
ancil_general_regrid_3d_to_3d_split1	succeeded
ancil_fill_n_merge_invert_mask_kdtree	succeeded
ancil_general_regrid_invert_mask_spiral_split2	succeeded
build_docs	succeeded
ancil_general_regrid_invert_mask_latitude_weighted_kdtree_split2	succeeded
ancil_general_regrid_with_time_constraint_latitude_weighted_kdtree_split0	succeeded
ancil_general_regrid_grid_to_variable_resolution_grid_split1	succeeded
ancil_general_regrid_with_time_constraint_latitude_weighted_kdtree_split1	succeeded
ancil_general_regrid_grid_to_grid_spiral_split0	succeeded
ancil_general_regrid_invert_mask_kdtree_split0	succeeded
ancil_general_regrid_3d_to_3d_split0	succeeded
ancil_general_regrid_3d_to_3d_with_extrapolation_split0	succeeded
ancil_general_regrid_with_time_constraint_spiral_split2	succeeded
ancil_general_regrid_grid_to_grid_latitude_weighted_kdtree_split1	succeeded
ancil_fill_n_merge_invert_mask_latitude_weighted_kdtree	succeeded
ancil_general_regrid_grid_to_n48_namelist_split1	succeeded
ancil_general_regrid_invert_mask_latitude_weighted_kdtree_split0	succeeded
flake8	succeeded
ancil_general_regrid_grid_to_grid_spiral_split2	succeeded
ancil_general_regrid_grid_to_n48e_namelist_split2	succeeded
ancil_general_regrid_grid_to_variable_resolution_grid_split2	succeeded
ancil_general_regrid_3d_to_3d_with_extrapolation_split1	succeeded
ancil_fill_n_merge_invert_mask_spiral	succeeded
ancil_general_regrid_grid_to_n48e_namelist_split1	succeeded
ancil_2anc_split0	succeeded
ancil_general_regrid_invert_mask_spiral_split0	succeeded
ancil_general_regrid_invert_mask_kdtree_split2	succeeded
ancil_general_regrid_grid_to_grid_kdtree_split1	succeeded
ancil_general_regrid_grid_to_grid_latitude_weighted_kdtree_split2	succeeded
ancil_general_regrid_grid_to_n48_namelist_split2	succeeded
ancil_general_regrid_invert_mask_spiral_split1	succeeded
ancil_create_ite_shapefile	succeeded
black	succeeded
ancil_general_regrid_with_time_constraint_kdtree_split0	succeeded
ancil_general_regrid_with_time_constraint_latitude_weighted_kdtree_split2	succeeded
ancil_general_regrid_with_time_constraint_kdtree_split2	succeeded
ancil_general_regrid_grid_to_grid_kdtree_split0	succeeded
ancil_general_regrid_grid_to_grid_kdtree_split2	succeeded
ancil_general_regrid_grid_to_n48e_namelist_split0	succeeded
ancil_general_regrid_grid_to_variable_resolution_grid_split0	succeeded
unittests	failed
ancil_general_regrid_invert_mask_kdtree_split1	succeeded
ancil_general_regrid_3d_to_3d_with_extrapolation_split2	succeeded
ancil_general_regrid_with_time_constraint_spiral_split0	succeeded
ancil_general_regrid_invert_mask_latitude_weighted_kdtree_split1	succeeded
ancil_fill_n_merge_land_cover_spiral	succeeded
ancil_fill_n_merge_land_cover_latitude_weighted_kdtree	succeeded
ancil_fill_n_merge_land_cover_kdtree	succeeded
rose_ana_2anc	succeeded
rose_ana_general_regrid_latitude_weighted_kdtree	failed
rose_ana_fill_n_merge	succeeded
rose_ana_general_regrid	failed
rose_ana_general_regrid_spiral	failed
rose_ana_general_regrid_kdtree	failed
linkcheck	failed
plot_comparisons_general_regrid_kdtree	succeeded
plot_comparisons_general_regrid_latitude_weighted_kdtree	succeeded
plot_comparisons_general_regrid_spiral	succeeded
plot_comparisons_general_regrid	succeeded

Wed 16 Sep 15:24:02 BST 2026 Git status: [ " M app/install_cold/rose-app.conf", " M flow.cylc" ] Commit: 7db18b5beaff2693096e2be9943c978680c0223e

---

Test Results - Summary

tasks	total
failed	44
succeeded	183
waiting	15

Test Results - Detail

task	status
install_cold	succeeded
lai_unittests	failed
flake8	failed
ancil_dms_chloro_climatology_dms	succeeded
ancil_soil_roughness_preproc_split1	succeeded
lct_unittests	failed
ancil_river_routing_1d_river_coupling_split0	succeeded
soil_dust_unittests	succeeded
ancil_soil_roughness_preproc_split2	succeeded
ancil_orography_filtered_preproc_globe30	succeeded
ancil_lake_depth_preproc	succeeded
ancil_lct_preproc_cci_split2	waiting
river_routing_unittests	succeeded
ancil_soil_albedo_split1	succeeded
ancil_sst_seaice_preproc_HadISST	failed
ancil_dms_chloro_climatology_chl	succeeded
ancil_prescribed_time_varying_veg_split0	succeeded
ancil_river_routing_1d_river_coupling_split2	succeeded
topographic_index_unittests	succeeded
ancil_river_routing_gc6_split2	succeeded
cmip7_utils_unittests	succeeded
soils_unittests	succeeded
ancil_lai_split1	succeeded
ancil_river_routing_gc6_split1	succeeded
cmip7_dms_chloro_unittests	succeeded
ancil_ozone_redistribution_gregorian	failed
isort	succeeded
ancil_lai_high_res_split2	succeeded
ancil_soils_clapp_hornberger_split2	succeeded
prescribed_time_varying_veg_unittests	succeeded
ancil_river_routing_preproc	succeeded
ancil_easy_aerosol_preproc_easy_absorption_lw	succeeded
ancil_soil_roughness_preproc_split0	succeeded
ancil_soil_roughness_split2	succeeded
ancil_soils_clapp_hornberger_split0	succeeded
ancil_sample_tracemalloc_split1	succeeded
ancil_lct_preproc_cci_split0	failed
ancil_canopy_heights_split1	succeeded
ancil_generate_masks_split2	succeeded
ancil_generate_masks_split0	succeeded
black	failed
ancil_orographic_formdrag_preproc	succeeded
ancil_pop_den	succeeded
ancil_river_storage_preproc	succeeded
ancil_lct_preproc_ite_split1	succeeded
ancil_canopy_heights_split2	succeeded
ancil_easy_aerosol_preproc_easy_extinction_sw	succeeded
sample_unittests	failed
ancil_easy_aerosol_preproc_easy_cdnc	succeeded
ancil_sst_seaice_preproc_oper_AMM15_UKV	succeeded
ancil_lct_preproc_igbp_split2	succeeded
ancil_lct_preproc_cci_split1	waiting
ancil_lct_preproc_igbp_split1	succeeded
ancil_lct_preproc_ite_split2	succeeded
ancil_coastal_distance_unittests	succeeded
soil_roughness_unittests	succeeded
ancil_soil_roughness_split1	succeeded
ancil_lai_split0	succeeded
ancil_sample_tracemalloc_split0	succeeded
ancil_lct_cci_split0	waiting
ancil_pop_den_hyde_preproc	succeeded
ancil_easy_aerosol_preproc_easy_extinction_lw	succeeded
ancil_lai_high_res_split1	succeeded
ancil_lct_postproc_c4_split1	waiting
ancil_lct_preproc_ite_split0	succeeded
ancil_soil_albedo_split2	succeeded
ozone_redistribution_unittests	succeeded
ancil_orography_filtered_preproc_gmted_ramp2	succeeded
river_storage_unittests	succeeded
ancil_sample_split0	succeeded
ancil_orographic_wavedrag_preproc_globe30	succeeded
ancil_model_derived_sst_si_climatology_cmip7_si	succeeded
sst_cmip7_unittests	succeeded
ancil_generate_masks_split1	succeeded
ancil_soil_albedo_split0	succeeded
ancil_prescribed_time_varying_veg_split1	succeeded
orography_unittests	succeeded
canopy_heights_unittests	succeeded
ancil_soils_clapp_hornberger_split1	succeeded
ancil_topographic_index_preproc	succeeded
ancil_dms_chloro_timeseries_chl	succeeded
ancil_river_routing_1d_river_coupling_split1	succeeded
ancil_lct_preproc_igbp_split0	succeeded
sst_seaice_unittests	succeeded
ancil_model_derived_sst_si_climatology_cmip7_sst	succeeded
ancil_model_derived_sst_si_timeseries_cmip7_si	succeeded
ancil_easy_aerosol_preproc_easy_asymmetry_sw	succeeded
ancil_lct_postproc_c4_split2	waiting
ancil_sample_tracemalloc_split2	succeeded
ancil_river_routing_gc6_split0	succeeded
ancil_orography_unfiltered_preproc_globe30	succeeded
ancil_lct_postproc_c4_split0	waiting
ancil_lai_high_res_split0	succeeded
ancil_easy_aerosol_preproc_easy_asymmetry_lw	succeeded
ancil_sample_split1	succeeded
ancil_lai_split2	succeeded
ancil_orography_unfiltered_preproc_gmted_ramp2	succeeded
ancil_ozone_redistribution_360_day	failed
ancil_dms_chloro_timeseries_dms	succeeded
ancil_sample_split2	succeeded
ancil_lct_cci_split1	waiting
pop_den_unittests	succeeded
ancil_canopy_heights_split0	succeeded
ancil_prescribed_time_varying_veg_split2	succeeded
ancil_model_derived_sst_si_timeseries_cmip7_sst	succeeded
ancil_lct_cci_split2	waiting
ancil_soil_roughness_split0	succeeded
ancil_easy_aerosol_preproc_easy_absorption_sw	succeeded
ancil_coastal_distance	succeeded
rose_ana_dms_chloro_climatology_dms	succeeded
rose_ana_dms_chloro_climatology_chl	succeeded
rose_ana_lai	failed
ancil_orography_mean_blended_max_slope_0p01_max_smooth_1_globe30_split1	succeeded
ancil_orography_mean_blended_max_slope_0p01_max_smooth_1_globe30_split2	succeeded
ancil_orography_mean_epsilon_value_globe30_split2	succeeded
ancil_orography_mean_epsilon_value_globe30_split1	succeeded
ancil_orography_mean_blended_max_slope_0p01_max_smooth_1_globe30_split0	succeeded
ancil_orography_mean_epsilon_value_globe30_split0	succeeded
ancil_soil_roughness_regrid_split2	succeeded
ancil_soil_roughness_regrid_split1	succeeded
rose_ana_soil_albedo	failed
rose_ana_prescribed_time_varying_veg	failed
rose_ana_lake_depth_preproc	succeeded
rose_ana_soils	succeeded
ancil_soil_dust_split2	succeeded
rose_ana_lai_high_res	failed
rose_ana_canopy_heights	failed
ancil_soil_dust_split0	succeeded
ancil_river_storage_gc6	succeeded
ancil_river_storage_1d_river_coupling	succeeded
ancil_lct_ite_split1	failed
rose_ana_easy_aerosol_preproc	succeeded
ancil_river_routing_gc4_split0	succeeded
ancil_river_routing_gc4_split2	succeeded
ancil_river_routing_gc4_split1	succeeded
ancil_soil_roughness_regrid_split0	succeeded
ancil_lct_ite_split2	failed
ancil_orographic_formdrag_split2	succeeded
ancil_orographic_formdrag_split1	succeeded
ancil_orographic_formdrag_split0	succeeded
ancil_add_lakes	waiting
ancil_lct_igbp_split1	failed
ancil_sst_seaice_oper_AMM15_UKV_split2	succeeded
ancil_sst_seaice_oper_AMM15_UKV_split0	succeeded
ancil_sst_seaice_oper_AMM15_UKV_split1	succeeded
ancil_lct_igbp_split2	succeeded
rose_ana_pop_den	succeeded
ancil_lct_ite_split0	failed
ancil_orography_mean_blended_max_slope_0p01_max_smooth_1_gmted_ramp2_split1	succeeded
ancil_orography_mean_blended_max_slope_from_smooth_dilation_gmted_ramp2_split0	succeeded
ancil_orography_mean_epsilon_default_gmted_ramp2_split2	succeeded
ancil_orography_mean_epsilon_value_rotated_pole_LAM_split1	succeeded
ancil_orography_mean_blended_max_slope_from_smooth_dilation_gmted_ramp2_split1	succeeded
ancil_orography_mean_blended_max_slope_0p01_max_smooth_1_gmted_ramp2_split2	succeeded
ancil_orography_mean_epsilon_value_gmted_ramp2_split0	succeeded
ancil_orography_mean_epsilon_value_rotated_pole_LAM_split0	succeeded
ancil_orography_mean_epsilon_value_gmted_ramp2_split2	succeeded
ancil_orography_mean_blended_max_slope_from_smooth_dilation_gmted_ramp2_split2	succeeded
ancil_orography_mean_blended_max_slope_0p01_max_smooth_1_gmted_ramp2_split0	succeeded
ancil_orography_mean_epsilon_default_gmted_ramp2_split1	succeeded
ancil_orography_mean_epsilon_value_gmted_ramp2_split1	succeeded
ancil_orography_mean_epsilon_value_rotated_pole_LAM_split2	succeeded
rose_ana_orographic_wavedrag_gmted_ramp2	failed
ancil_orography_mean_epsilon_default_gmted_ramp2_split0	succeeded
rose_ana_orographic_wavedrag_globe30	failed
ancil_topographic_index_split2	waiting
ancil_topographic_index_split1	waiting
ancil_topographic_index_split0	waiting
rose_ana_dms_chloro_timeseries_chl	succeeded
ancil_lct_igbp_split0	succeeded
rose_ana_sample	failed
ancil_soil_dust_split1	succeeded
rose_ana_model_derived_sst_si_climatology_cmip7_si	succeeded
rose_ana_dms_chloro_timeseries_dms	succeeded
rose_ana_coastal_distance	failed
rose_ana_model_derived_sst_si_climatology_cmip7_sst	succeeded
rose_ana_model_derived_sst_si_timeseries_cmip7_si	succeeded
ancil_soil_roughness_postproc_split2	succeeded
ancil_radiation_parameters_split1	succeeded
ancil_radiation_parameters_split0	succeeded
ancil_radiation_parameters_split2	succeeded
ancil_orography_slopes_preproc	succeeded
rose_ana_river_routing	failed
ancil_soil_roughness_postproc_split1	succeeded
rose_ana_model_derived_sst_si_timeseries_cmip7_sst	succeeded
rose_ana_sample_tracemalloc	failed
rose_ana_soil_dust	succeeded
rose_ana_sst_seaice	waiting
ancil_soil_roughness_postproc_split0	succeeded
rose_ana_orographic_formdrag	failed
move_lct_files_split0	waiting
ancil_orographic_wavedrag_epsilon_value_globe30_split1	succeeded
rose_ana_orography_mean_globe30	failed
ancil_orography_submean_height_globe30	succeeded
ancil_orographic_wavedrag_epsilon_value_globe30_split2	succeeded
rose_ana_orography_blended_mean_globe30	failed
ancil_orographic_wavedrag_blended_max_slope_0p01_max_smooth_1_globe30_split0	succeeded
ancil_orographic_wavedrag_epsilon_value_globe30_split0	succeeded
ancil_orographic_wavedrag_blended_max_slope_0p01_max_smooth_1_globe30_split1	succeeded
ancil_orographic_wavedrag_blended_max_slope_0p01_max_smooth_1_globe30_split2	succeeded
rose_ana_soil_roughness	failed
ancil_orographic_wavedrag_blended_max_slope_from_smooth_dilation_gmted_ramp2_split2	succeeded
rose_ana_orography_dilation_mean_gmted_ramp2	failed
ancil_orographic_wavedrag_epsilon_default_gmted_ramp2_split0	succeeded
ancil_orography_submean_height_gmted_ramp2	succeeded
ancil_orographic_wavedrag_epsilon_default_45_deg_polar_cutoff_gmted_ramp2_split0	succeeded
rose_ana_orography_mean_gmted_ramp2	failed
ancil_orographic_wavedrag_blended_max_slope_from_smooth_dilation_gmted_ramp2_split0	succeeded
ancil_orographic_wavedrag_blended_max_slope_0p01_max_smooth_1_gmted_ramp2_split2	succeeded
ancil_orographic_wavedrag_blended_max_slope_0p01_max_smooth_1_gmted_ramp2_split0	succeeded
rose_ana_orography_mean_LAM	failed
ancil_orographic_wavedrag_epsilon_value_rotated_pole_LAM_split0	succeeded
ancil_orography_submean_height_LAM	succeeded
ancil_orographic_wavedrag_epsilon_value_gmted_ramp2_split2	succeeded
ancil_orographic_wavedrag_blended_max_slope_0p01_max_smooth_1_gmted_ramp2_split1	succeeded
ancil_orographic_wavedrag_epsilon_default_45_deg_polar_cutoff_gmted_ramp2_split2	succeeded
ancil_orographic_wavedrag_epsilon_default_gmted_ramp2_split2	succeeded
ancil_orographic_wavedrag_epsilon_value_rotated_pole_LAM_split1	succeeded
ancil_orographic_wavedrag_epsilon_value_rotated_pole_LAM_split2	succeeded
ancil_orographic_wavedrag_epsilon_default_45_deg_polar_cutoff_gmted_ramp2_split1	succeeded
ancil_orographic_wavedrag_epsilon_default_gmted_ramp2_split1	succeeded
ancil_orographic_wavedrag_epsilon_value_gmted_ramp2_split1	succeeded
ancil_orographic_wavedrag_epsilon_value_gmted_ramp2_split0	succeeded
ancil_orographic_wavedrag_blended_max_slope_from_smooth_dilation_gmted_ramp2_split1	succeeded
rose_ana_river_storage	failed
rose_ana_orography_submean_height_globe30	failed
ancil_orography_submean_gradient_globe30	succeeded
rose_ana_radiation_parameters	failed
move_lct_files_split2	waiting
rose_ana_orography_blended_globe30	failed
rose_ana_orography_slopes_preproc	succeeded
rose_ana_45_deg_polar_cutoff_gmted_ramp2	failed
rose_ana_orography_dilation_gmted_ramp2	failed
rose_ana_orography_blended_gmted_ramp2	failed
rose_ana_orographic_wavedrag_LAM	failed
rose_ana_orography_submean_height_LAM	failed
ancil_orography_submean_gradient_LAM	succeeded
ancil_orography_submean_gradient_gmted_ramp2	succeeded
rose_ana_orography_submean_height_gmted_ramp2	failed
rose_ana_orography_submean_gradient_globe30	failed
rose_ana_orography_submean_gradient_LAM	failed
rose_ana_orography_submean_gradient_gmted_ramp2	failed

[alasdair-roy]

The main issue was fixing the failing unittest for transform_bbox. Originally the test failed when a polygon spanning the entire globe was passed. Now this no longer happens. It's not completely clear what was meant to be tested here.

Should a global polygon fail?

1. Transforming from the UMsphere to UMsphere with a global polygon does not fail in the original environment
2. You can decrease the polygon by a very small number and then the test starts failing in the old env
3. You can centre the global polygon at the origin of the OSGB and the test no longer raises an error in the old environment

Issues:

1. The OSGB in ANTS does not have the same projection limits as the OSGB in cartopy (this seems to be on purpose)
2. The OSGB in ANTS has the general cartopy hard-coded domain limits of (-2e7, -1e7, 2e7, 1e7), regardless of origin specified when creating the osgb in iris. The origin does not seem to factor into the bounds clipping in the same way when converted from an iris crs.
3. Depending on how large the polygon is / how close to the boundaries of the domain, cartopy can end up walking the polygon around the outside of the domain so the bounds that come out are (-2e7, -1e7, 2e7, 1e7) for a range of polygons.
4. Sometimes polygons do return NaN bounds
5. The data limits of an iris cube and the domain limits of cartopy are two separate things. The domain limit of the cartopy osgb is (0,0,7e5, 13e5).

I decided to implement a check that the returned bounds are invertible, as these bounds do not seem to be. This means that cases with clipped bounds will fail and not just the global polygon. I don't think that the original test case would reach transform_bbox from _extract_overlap anyway as the initial points depend on the domain of the data in the iris cube.

Relevant links:

1. No warning if extents past limits are clipped SciTools/cartopy#1730
2. https://code.metoffice.gov.uk/trac/ancil/ticket/278
3. https://ppmo-iris.readthedocs.io/en/latest/_modules/iris/coord_systems.html#OSGB

Polygon navigating exterior of domain: