tests/test-log-exthook.t

changegroup: replace changegroup with makechangegroup

As part of reducing the number of changegroup creation APIs, let's replace the
changegroup function with makechangegroup. This pushes the responsibility of
creating the outgoing set to the caller, but that seems like a simple and
reasonable concept for the caller to be aware of.

Differential Revision: https://phab.mercurial-scm.org/D668

Test hg log changeset printer external hook
-------------------------------------------

  $ cat > $TESTTMP/logexthook.py <<EOF
  > from __future__ import absolute_import
  > from mercurial import (
  >   cmdutil,
  >   commands,
  >   repair,
  > )
  > def rot13description(self, ctx):
  >     summary = "summary".encode('rot13')
  >     description = ctx.description().strip().splitlines()[0].encode('rot13')
  >     self.ui.write("%s:     %s\n" % (summary, description))
  > def reposetup(ui, repo):
  >     cmdutil.changeset_printer._exthook = rot13description
  > EOF

Prepare the repository

  $ hg init empty
  $ cd empty
  $ touch ROOT
  $ hg commit -A -m "Root" ROOT

  $ touch a b c
  $ hg commit -A -m "Add A, B, C" a b c

Check the log

  $ hg log --config extensions.t=$TESTTMP/logexthook.py
  changeset:   1:70fc82b23320
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  fhzznel:     Nqq N, O, P
  summary:     Add A, B, C
  
  changeset:   0:b00443a54871
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  fhzznel:     Ebbg
  summary:     Root
  
Check that exthook is working with graph log too

  $ hg log -G --config extensions.t=$TESTTMP/logexthook.py
  @  changeset:   1:70fc82b23320
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  fhzznel:     Nqq N, O, P
  |  summary:     Add A, B, C
  |
  o  changeset:   0:b00443a54871
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     fhzznel:     Ebbg
     summary:     Root