These tests patch `<module>.subprocess.run`, which is the shared `subprocess`
module singleton, so the patch is process-wide. Importing `tui_gateway.server`
runs `prefetch_update_check()` at import time, spawning an unnamed daemon thread
(`Thread-N (_run)`) that shells out to `git ... origin` (`text=True, timeout=5`).
That call races the test and lands in the captured list, intermittently failing
`test_tui_gateway_fuzzy_file_listing_hides_git_windows` with either
`KeyError: 'creationflags'` (the daemon's git call has no creationflags) or a
call-count mismatch (3 git calls captured, not 2). It only reproduced under the
parallel test harness because of the extra concurrency/timing.
Filter captured calls to the distinctive argv tokens of the call under test
(`--show-toplevel`, `ls-files`, `branch --show-current`, `diff`, `rg`,
`taskkill`) and read `creationflags` via `.get`, mirroring the existing
hardening on `test_gateway_pid_scan_hides_wmic_and_powershell_windows`. The
production code is unchanged; this is a test-isolation fix.
Brooklyn Nicholson
0ea318a7d4