tests/test-default-push

Add extension to provide the 'hg children' command (with tests)

#!/bin/sh

hg init a
echo a > a/a
hg --cwd a ci -Ama

hg clone a c

hg clone a b
echo b >> b/a
hg --cwd b ci -mb

echo % push should push to default when default-push not set
hg --cwd b push | sed 's/pushing to.*/pushing/'

echo % push should push to default-push when set
echo 'default-push = ../c' >> b/.hg/hgrc
hg --cwd b push | sed 's/pushing to.*/pushing/'