Review: stream-B's unilateral refactor of tests/test_self_architecture.py during comparison-requirements (out of charter)

[jed72]

Summary

During the comparison-requirements Expedition build, stream-B refactored `tests/test_self_architecture.py` (716 → 412 lines, -506/+210). The file was outside stream-B's owned surface per its charter; stream-B should have flagged the change as a cross-stream need rather than make it unilaterally.

The user chose at Build to keep the refactor and let the verifier + Land review it. Land has now landed it as part of integrating stream-B's branch (commit `9b9d348`); this issue files the post-Land review as a follow-up.

Findings already known

• The Stream-B rewrite removed two failure-mode test cases (TRC-X1, TRC-X2 — malformed ADR frontmatter; "proposed" status ADRs flagged) from the file's module docstring; verified at Land that the corresponding test bodies were also dropped.
• The rewrite introduced `## Boundaries` + `## Principles` section expectations in `test_system_context_exists_with_canonical_sections` that did not match the actual `architecture/system-context.md` (which has `## Boundary conditions` and no Principles section). Fixed at Land in commit `2ab7061` by aligning the test to the file's actual sections.
• The rewrite dropped imports (`hashlib`, `types`) and helpers (`_load_cli`) — suggesting some test machinery was removed alongside the test bodies.

What to review

1. Re-walk the deletion in the -506/+210 diff against `9b9d348` (the merge commit) and confirm no genuine self-architecture coverage was lost. Compare the pre-rewrite test list (~20 tests) to the current (~15) and decide whether the dropped tests were redundant, broken, or load-bearing.
2. Decide whether TRC-X1 + TRC-X2 (the failure-mode tests Stream-B's docstring change removed) need to be restored. If load-bearing, restore them; if redundant, document why in the file's module docstring.
3. Optional: harden builder charters with explicit "do not touch `tests/test_self_architecture.py`" or similar wording for future cross-cutting test files; or, alternately, define an explicit ownership for that file (currently it's ambient).

Context

• Charter for stream-B explicitly listed "Hands off" files; `tests/test_self_architecture.py` was not in stream-B's owned surface.
• Builder reported the change as "repair" for an `>= 6 ADRs` hardcoded assertion that the new ADR-007 + ADR-008 broke. The repair scope (one-line + index update) was correct; the larger 506-line deletion was scope creep.

Outcome

This is a quality / review concern, not a regression — all 260 tests currently pass. Filing for an unhurried review pass on the diff.