Refactor LFRic-XIOS testing infrastructure

[Ed Hone (EdHone)]

PR Summary

Sci/Tech Reviewer: mo-lucy-gordon
Code Reviewer: Ricky Wong (@mo-rickywong)

This PR refactors the testing infrastructure of the LFRic-XIOS component, namely by:

• removing the matlpotlib and xarray dependencies from the default testing workflow
  • this necessitated the use of more explicit KGO checking, so more KGOs have been added
  • the plotting functionality is too useful to be destroyed, so has been disabled by default and can be run by using the PLOT_TEST_OUTPUT=true environment variable.
  • scitools has been removed as a module dependency of the compiler technical tests on Met Office machines.
• refactoring the tests' python code to be PEP8 compliant, as specified in the LFRic python coding standards
  • running pylint on all individual python files in the LFRic-XIOS component should now show no issues.
• copywrite statements have been updated to the new style.

Code Quality Checklist

• I have performed a self-review of my own code
• My code follows the project's style guidelines
• Comments have been included that aid understanding and enhance the readability of the code
• My changes generate no new warnings
• All automated checks in the CI pipeline have completed successfully

Testing

• I have tested this change locally, using the LFRic Core rose-stem suite
• If required (e.g. API changes) I have also run the LFRic Apps test suite using this branch
• If any tests fail (rose-stem or CI) the reason is understood and acceptable (e.g. kgo changes)
• I have added tests to cover new functionality as appropriate (e.g. system tests, unit tests, etc.)
• Any new tests have been assigned an appropriate amount of compute resource and have been allocated to an appropriate testing group (i.e. the developer tests are for jobs which use a small amount of compute resource and complete in a matter of minutes)

trac.log

Test Suite Results - lfric_core - lfric_core-348-lfx-test-refactor/run5

Suite Information

Item	Value
Suite Name	lfric_core-348-lfx-test-refactor/run5
Suite User	edward.hone
Workflow Start	2026-05-01T10:32:18
Groups Run	developer

Dependency	Reference	Main Like
lfric_core	EdHone/lfric_core@348-lfx-test-refactor	False
SimSys_Scripts	MetOffice/SimSys_Scripts@cab3315	True

Task Information

✅ succeeded tasks - 390

Security Considerations

• I have reviewed my changes for potential security issues
• Sensitive data is properly handled (if applicable)
• Authentication and authorisation are properly implemented (if applicable)

Performance Impact

• Performance of the code has been considered and, if applicable, suitable performance measurements have been conducted

AI Assistance and Attribution

• Some of the content of this change has been produced with the assistance of Generative AI tool name (e.g., Met Office Github Copilot Enterprise, Github Copilot Personal, ChatGPT GPT-4, etc) and I have followed the Simulation Systems AI policy (including attribution labels)

Documentation

• Where appropriate I have updated documentation related to this change and confirmed that it builds correctly

PSyclone Approval

• If you have edited any PSyclone-related code (e.g. PSyKAl-lite, Kernel interface, optimisation scripts, LFRic data structure code) then please contact the TCD Team

Sci/Tech Review

• I understand this area of code and the changes being added
• The proposed changes correspond to the pull request description
• Documentation is sufficient (do documentation papers need updating)
• Sufficient testing has been completed

(Please alert the code reviewer via a tag when you have approved the SR)

Code Review

• All dependencies have been resolved
• Related Issues have been properly linked and addressed
• CLA compliance has been confirmed
• Code quality standards have been met
• Tests are adequate and have passed
• Documentation is complete and accurate
• Security considerations have been addressed
• Performance impact is acceptable

[mo-lucy-gordon]

I think this code looks good, but I am wondering whether it might be good to add/edit a few lines to documentation about the availability and use of the plotting function?

[Ed Hone (EdHone)]

I think this code looks good, but I am wondering whether it might be good to add/edit a few lines to documentation about the availability and use of the plotting function?

I just added a readme and updated the page in the docs in the latest 2 commits

[mo-lucy-gordon]

To Steve Mullerworth (@stevemullerworth) for code review

[Ed Hone (EdHone)]

To Steve Mullerworth (Steve Mullerworth (@stevemullerworth)) for code review

Potentially to Ricky Wong (@mo-rickywong) now

[Ed Hone (EdHone)]

This has been merged up to the head of main and updated - could I get another review please? mo-lucy-gordon Ricky Wong (@mo-rickywong)

[mo-lucy-gordon]

Ricky Wong (@mo-rickywong) back to you for CR

[Ricky Wong (mo-rickywong)]

Thanks for adding the README, goo to confirm the testing. Ran the unit-tests, though the is a non-existing variable attempted to be set. What's the cause of this, can this be sorted out?

Minor note: I know the branch was cut a while ago, though please refrain from naming with PR numbers at the "start" of of the branch name. I think it messes up the rose suite unless you rename the test-suite.

Test-suite runs green, though when attempting to run with plotting nothing happens.
loaded lfric modules and scitools, should I see plots? or png files to open?
I don't see much to comment on in the changes, though I'm checking the functionality and docs.