tests/test-push-checkheads-partial-C2.t

run-tests: extract sorting of tests to own function

TestRunner._run() is a large function and is difficult to follow.
Let's extract the test sorting to its own function to make it shorter.

When I refactored run-tests.py several years ago, I put a lot of
functionality in methods. The prevailing Mercurial style is to use
functions - not classes - where possible. While refactoring the code,
I decided to undo this historical mistake of mine by moving the code
to a standalone function.

Differential Revision: https://phab.mercurial-scm.org/D1750

====================================
Testing head checking code: Case C-2
====================================

Mercurial checks for the introduction of new heads on push. Evolution comes
into play to detect if existing branches on the server are being replaced by
some of the new one we push.

This case is part of a series of tests checking this behavior.

Category C: case were the branch is only partially obsoleted
TestCase 2: 2 changeset branch, only the base is rewritten

.. old-state:
..
.. * 2 changeset branch
..
.. new-state:
..
.. * 1 new changesets branches superceeding only the base of the old one
.. * The old branch is still alive (base is obsolete, head is alive)
..
.. expected-result:
..
.. * push denied
..
.. graph-summary:
..
..   B ○
..     |
..   A ø⇠◔ A'
..     |/
..     ●

  $ . $TESTDIR/testlib/push-checkheads-util.sh

Test setup
----------

  $ mkdir C2
  $ cd C2
  $ setuprepos
  creating basic server and client repo
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd server
  $ mkcommit B0
  $ cd ../client
  $ hg pull
  pulling from $TESTTMP/C2/server
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets d73caddc5533
  (run 'hg update' to get a working copy)
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit A1
  created new head
  $ hg debugobsolete `getid "desc(A0)" ` `getid "desc(A1)"`
  obsoleted 1 changesets
  $ hg log -G --hidden
  @  f6082bc4ffef (draft): A1
  |
  | o  d73caddc5533 (draft): B0
  | |
  | x  8aaa48160adc (draft): A0
  |/
  o  1e4be0697311 (public): root
  

Actual testing
--------------

  $ hg push --rev 'desc(A1)'
  pushing to $TESTTMP/C2/server
  searching for changes
  abort: push creates new remote head f6082bc4ffef!
  (merge or see 'hg help push' for details about pushing new heads)
  [255]

  $ cd ../..