test(alias): cover invalid signature JSON error

[overtrue]

Related issue(s)

None.

Background

Recent alias validation changes made local alias set usage errors go through the JSON-aware formatter. The existing regression covered embedded endpoint credentials, but the invalid --signature branch was still unpinned.

Solution

Add a focused subprocess error-contract test for rc alias set --signature v5 --json. The test asserts stderr JSON metadata, exit code 2, empty stdout, and that no alias is persisted after validation fails.

Validation

• cargo test -p rustfs-cli --test error_contract alias_set_json_error_rejects_invalid_signature
• make pre-commit

[Copilot]

Pull request overview

Adds a regression test to pin the JSON error contract for rc alias set when --signature is invalid, ensuring CLI usage validation failures produce structured JSON on stderr and do not persist config changes.

Changes:

• Add a subprocess-based error-contract test for rc alias set --signature v5 --json.
• Assert exit code 2, empty stdout, and JSON error metadata on stderr.
• Verify no alias is persisted after validation fails by checking rc alias list --json.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.