Per plan D7 (rollback semantics) and codex #10 (rollback scope). The
/setup-gbrain skill instructs the model to follow a specific shell
sequence when running `gbrain init --pglite` against an existing
config:
1. mv ~/.gbrain/config.json ~/.gbrain/config.json.gstack-bak-<ts>
2. gbrain init --pglite --json
3. on non-zero exit: mv .bak back; surface error
This test verifies that contract using a fake `gbrain` binary that
fails on init. Three cases:
- FAILURE: gbrain init exits non-zero → broken config restored to
original path, no leftover .bak.
- SUCCESS: gbrain init exits 0 → new config in place, .bak survives
for audit (user reviews + deletes manually).
- SCOPE: any partial PGLite directory at ~/.gbrain/pglite/ is NOT
auto-cleaned. We only promise to restore config.json; PGLite
cleanup is the user's call (codex #10).
If the skill template rewrites this sequence in a future change, this
test should fail until the test's shell is updated too. That's the
point — keep the test and the skill template aligned.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Garry Tan