#1 -> can simulate with pkill or touching any files under watch via `--pantsd-invalidation-globs`; #2 -> maybe a similar test harness launching a SimpleHTTPServer on the same bind port?; #3 -> can insert e.g. a

raise

in e.g. the pailgun execution path and then ensure the client handles the case of a broken daemon well (and e.g. at least detects, retries and/or attempts to restart the daemon + retry)