tests/test-children.t

revsetbenchmarks: allow running multiple variants per revset

The current benchmarks were only testing the whole iteration. This is suboptimal
because some changes are meaningful for things like first result, minimum or
sorting.

We introduce a "variants" feature that let you systematically add some variants
to all revsets tested.

A typical variants value would be 'plain,min,last,sort'. When testing 'all()' it
will also provide testing for:
- all()
- min(all())
- last(all())
- sort(sort)

and output:

   plain         min            last           sort
0) 0.034568      0.037857       0.000074       0.034238
1) 0.011358  32% 0.020181  53%  0.000080 108%  0.011405  33%

Using revsets (who hit the API) instead of the internal API add some overhead,
but the overhead should be the same everywhere so it still allow comparison.
This is is more simple to implement and allows comparison with older versions
who do not have the same API.

test children command

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > children =
  > EOF

init
  $ hg init t
  $ cd t

no working directory
  $ hg children

setup
  $ echo 0 > file0
  $ hg ci -qAm 0 -d '0 0'

  $ echo 1 > file1
  $ hg ci -qAm 1 -d '1 0'

  $ echo 2 >> file0
  $ hg ci -qAm 2 -d '2 0'

  $ hg co null
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo 3 > file3
  $ hg ci -qAm 3 -d '3 0'

hg children at revision 3 (tip)
  $ hg children

  $ hg co null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

hg children at nullrev (should be 0 and 3)
  $ hg children
  changeset:   0:4df8521a7374
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0
  
  changeset:   3:e2962852269d
  tag:         tip
  parent:      -1:000000000000
  user:        test
  date:        Thu Jan 01 00:00:03 1970 +0000
  summary:     3
  
  $ hg co 1
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

hg children at revision 1 (should be 2)
  $ hg children
  changeset:   2:8f5eea5023c2
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     2
  
  $ hg co 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

hg children at revision 2 (other head)
  $ hg children

  $ for i in null 0 1 2 3; do
  > echo "hg children -r $i"
  > hg children -r $i
  > done
  hg children -r null
  changeset:   0:4df8521a7374
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0
  
  changeset:   3:e2962852269d
  tag:         tip
  parent:      -1:000000000000
  user:        test
  date:        Thu Jan 01 00:00:03 1970 +0000
  summary:     3
  
  hg children -r 0
  changeset:   1:708c093edef0
  user:        test
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     1
  
  hg children -r 1
  changeset:   2:8f5eea5023c2
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     2
  
  hg children -r 2
  hg children -r 3

hg children -r 0 file0 (should be 2)
  $ hg children -r 0 file0
  changeset:   2:8f5eea5023c2
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     2
  

hg children -r 1 file0 (should be 2)
  $ hg children -r 1 file0
  changeset:   2:8f5eea5023c2
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     2
  

  $ hg co 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

hg children file0 at revision 0 (should be 2)
  $ hg children file0
  changeset:   2:8f5eea5023c2
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     2
  

should be compatible with templater (don't pass fctx to displayer)
  $ hg children file0 -Tdefault
  changeset:   2:8f5eea5023c2
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     2
  

  $ cd ..