[Pedro Henrique Penna (ppenna)]

Summary

#952 changed the summarize job of .github/workflows/nvx-rs-mutants.yml but not its tests, and merged without CI, which a fork's pull request runs only once approved. Since then, dev fails two Linux tests that validate-nvx runs, so the NVX CLI job of every CI run fails:

• MutantsWorkflowStepTests.test_the_outcomes_of_every_shard_merge
• MutantsWorkflowStepTests.test_shards_that_report_nothing_fail_the_merge

Both run the merge step without MUTANTS_RESULT, which its set -u rejects (MUTANTS_RESULT: unbound variable). They also write each shard's lists under the old artifact name, which the step no longer reads: since #952, a shard's output lands at shards/<index>/, and the merge counts a shard as reported when its outcomes.json is there.

Changes

• _merge passes the mutants job's result as MUTANTS_RESULT, success unless a test says otherwise.
• The tests write each shard's lists with its outcomes.json under its index, as the staging step uploads them.
• The test of shards that report nothing adds lists without an outcomes.json, which the merge must neither count nor merge.
• A new test checks that a mutants job that failed or was skipped fails the merge before it merges or summarizes anything.

Validation

• On nvx-mshv-test (Azure Linux 3, Python 3.12), python3 -m unittest scripts/test_nvx_rs_mutants.py passes all 11 tests. At dev (d049844), the two tests above fail.
• ruff check, ruff format --check, and pyright (Linux and Windows) pass on the file.
• The tests skip on Windows, which runs no bash steps.
• A change to the CLI tests alone runs only the GitHub-hosted CI jobs.

[Copilot]

🟢 Approval recommended

No active review issues are reported for the mutation-workflow test updates.

No open issues 🎉

What changed in this PR

Updates the mutation-workflow tests to match the shard layout and merge checks introduced in #952, addressing the reported NVX CLI test failures.

Changes:

• Supplies MUTANTS_RESULT and uses index-based shard fixtures containing outcomes.json.
• Verifies that lists without outcomes.json are neither counted nor merged.
• Adds coverage for failed and skipped mutants jobs, checking that merging and summarization do not occur.

File	Description
scripts/​test_nvx_rs_mutants.py	Aligns merge fixtures with the workflow and expands failure-path assertions.

_{Review effort: Balanced}

[Pedro Henrique Penna (ppenna)]

Superseded by #1023, which merged at 21:58Z with the same fix to \scripts/test_nvx_rs_mutants.py\ while this was open. On nvx-mshv-test, \dev\ now passes \MutantsWorkflowStepTests\ again, so this is no longer needed.