Remove --basetemp=/var/tmp/pytest-solstone from pyproject.toml addopts and add TMPDIR=/var/tmp to the Makefile instead. The --basetemp flag pinned every pytest run to one absolute path; pytest wipes that path on startup (documented behavior), so concurrent runs (two hop lodes, or a lode + local make ci) destroyed each other's tmp state mid-test. Symptom was mysterious vanishing-file errors and the need for manual `rm -rf /var/tmp/pytest-solstone` rituals. TMPDIR=/var/tmp gets tests onto disk (preserving the original intent of fb0bba28 — /tmp is tmpfs and filled RAM repeatedly) while pytest's default per-run isolation (/var/tmp/pytest-of-jer/pytest-N/) handles concurrency correctly. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>