$ fastobs="$TESTDIR"/../hgext/hgfastobs.py
  $ echo 'from mercurial import obsolete ; obsolete._enabled = True' > enableobs.py
  $ cat >> $HGRCPATH <<EOF
  > [obsolete]
  > syncstrategy = boxfill
  > [extensions]
  > EOF
  $ echo "enable-obsolete = $PWD/enableobs.py" >> $HGRCPATH
  $ echo "fastobs = $fastobs" >> $HGRCPATH

  $ hg init alice
  $ hg init bob
  $ hg init trent
  $ cd alice
  $ echo a > a
  $ hg addr && hg ci -m 'add a'
  adding a
  $ echo aa >> a
  $ hg ci -m 'edit a'
  $ echo aa > a
  $ hg ci --amend -m 'edit a'
  $ hg debugobsolete
  e772e827cd64564621e7e5af15c9f848e3b92c8e efa8cd969bc37e6a1330c29f4234fe9e9be681b3 0 {'date': '* 0', 'user': 'test'} (glob)
  5ccfcbc00f2a19cd7affedce5ff087e68e67c6cc 0 {'date': '* 0', 'user': 'test'} (glob)
  $ hg push ../trent
  pushing to ../trent
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  boxpush: about to transmit 2 obsolete markers (2 markers total)
  $ cd ../bob
  $ hg pull ../trent
  pulling from ../trent
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  (run 'hg update' to get a working copy)
  $ hg debugobsolete | sort
  5ccfcbc00f2a19cd7affedce5ff087e68e67c6cc 0 {'date': '* 0', 'user': 'test'} (glob)
  e772e827cd64564621e7e5af15c9f848e3b92c8e efa8cd969bc37e6a1330c29f4234fe9e9be681b3 0 {'date': '* 0', 'user': 'test'} (glob)