After running the functional test suite for a while, and encountering a hard-stop error, a number of "stale" mounts are left behind:

/dev/fuse on /GVFS.FT/test/238704f51ee541ec9049/src type fuse (rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)
/dev/fuse on /GVFS.FT/test/bd7025c836fa4cbe94d7/src type fuse (rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)
/dev/fuse on /GVFS.FT/test/f0fb2de381ea4a81a9a1/src type fuse (rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)

These may result when a functional test fails and doesn't clean up properly, or tries to clean up and unmount but a running process holds an open file handle within the mount.

The latter issue is one we will need to consider -- what should the action of gvfs unmount be when we cannot actually unmount the FUSE device?