TestFS 0.1.18

What's new in 0.1.18

A targeted release covering one fix that closes a silent-failure
class affecting Sparkle auto-update.

Reliability

• Sparkle pre-install hook gates updates on a clean unmount:
  an active testfs mount keeps the FSKit appex pinned in the kernel,
  and without intervention Sparkle's bundle replace fails silently —
  the user sees the new version in About box but /Applications/TestFS.app
  stays at the old version on disk. The host now runs an unmount
  sweep before allowing the install to proceed; on any failure the
  install is aborted loudly via an alert, leaving the user on the
  previous version with a clear message instead of a half-applied
  update (#65).

Auto-update

Existing 0.1.17 installs will pick this up via Sparkle within ~24 h
or immediately via App ▸ Check for Updates…. The hook is in 0.1.18,
so the next update from 0.1.18 onward (and every one after) is
gated by it. Updates into 0.1.18 still use the pre-hook flow —
unmount any active testfs volumes before accepting the prompt.

Out of scope (tracked)

• Manual drag-installs (no in-process hook) can still fail silently
  if a mount is active. Workaround: unmount first, then drag.