$ cat > loop.py <<EOF
  > from mercurial import commands
  > 
  > def loop(ui, loops, **opts):
  >     loops = int(loops)
  >     total = None
  >     if loops >= 0:
  >         total = loops
  >     if opts.get('total', None):
  >         total = int(opts.get('total'))
  >     loops = abs(loops)
  > 
  >     for i in range(loops):
  >         ui.progress('loop', i, 'loop.%d' % i, 'loopnum', total)
  >     ui.progress('loop', None, 'loop.done', 'loopnum', total)
  > 
  > commands.norepo += " loop"
  > 
  > cmdtable = {
  >     "loop": (loop, [('', 'total', '', 'override for total')],
  >              'hg loop LOOPS'),
  > }
  > EOF

  $ cat > filtercr.py <<EOF
  > import sys, re
  > for line in sys.stdin:
  >     line = re.sub(r'\r+[^\n]', lambda m: '\n' + m.group()[-1:], line)
  >     sys.stdout.write(line)
  > print
  > EOF

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "progress=" >> $HGRCPATH
  $ echo "loop=`pwd`/loop.py" >> $HGRCPATH
  $ echo "[progress]" >> $HGRCPATH
  $ echo "assume-tty=1" >> $HGRCPATH

test default params, display nothing because of delay

  $ hg -y loop 3 2>&1 | python filtercr.py
  
  $ echo "delay=0" >> $HGRCPATH
  $ echo "refresh=0" >> $HGRCPATH

test with delay=0, refresh=0

  $ hg -y loop 3 2>&1 | python filtercr.py
  
  loop [                                                                    ] 0/3
  loop [=====================>                                              ] 1/3
  loop [============================================>                       ] 2/3
                                                                                  \r (esc)

test refresh is taken in account

  $ hg -y --config progress.refresh=100 loop 3 2>&1 | python filtercr.py
  

test format options 1

  $ hg -y --config 'progress.format=number topic item+2' loop 2 2>&1 | python filtercr.py
  
  0/2 loop lo
  1/2 loop lo
                                                                                  \r (esc)

test format options 2

  $ hg -y --config 'progress.format=number item-3 bar' loop 2 2>&1 | python filtercr.py
  
  0/2 p.0 [                                                                     ]
  1/2 p.1 [=================================>                                   ]
                                                                                  \r (esc)

test format options and indeterminate progress

  $ hg -y --config 'progress.format=number item bar' loop -- -2 2>&1 | python filtercr.py
  
  0 loop.0               [ <=>                                                  ]
  1 loop.1               [  <=>                                                 ]
                                                                                  \r (esc)

make sure things don't fall over if count > total

  $ hg -y loop --total 4 6 2>&1 | python filtercr.py
  
  loop [                                                                    ] 0/4
  loop [================>                                                   ] 1/4
  loop [=================================>                                  ] 2/4
  loop [==================================================>                 ] 3/4
  loop [===================================================================>] 4/4
  loop [ <=>                                                                ] 5/4
                                                                                  \r (esc)

test immediate progress completion

  $ hg -y loop 0 2>&1 | python filtercr.py