$ hg init a

  $ echo a > a/a

  $ hg --cwd a ci -Ama

  adding a

  $ hg clone a c

  updating to branch default

  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg clone a b

  updating to branch default

  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo b >> b/a

  $ hg --cwd b ci -mb

Push should provide a hint when both 'default' and 'default-push' not set:

  $ cd c

  $ hg push --config paths.default=

  pushing to default-push

  abort: default repository not configured!

  (see the "path" section in "hg help config")

  [255]

  $ cd ..

Push should push to 'default' when 'default-push' not set:

  $ hg --cwd b push

  pushing to $TESTTMP/a (glob)

  searching for changes

  adding changesets

  adding manifests

  adding file changes

  added 1 changesets with 1 changes to 1 files

Push should push to 'default-push' when set:

  $ echo 'default-push = ../c' >> b/.hg/hgrc

  $ hg --cwd b push

  pushing to $TESTTMP/c (glob)

  searching for changes

  adding changesets

  adding manifests

  adding file changes

  added 1 changesets with 1 changes to 1 files