tests/test-hgk.t

tests: add test for issue5343 (grafting with copies)

It seems that issue5353 resulted in a lot of tests in test-graft.t,
but the bug actually reported in that issue didn't get a test
case. This patch adds one for the "move" and one for the "copy"
version of it. I also added a "copy+modify" case, to show what should
be a merge conflict. I didn't add one for the "backwards" version of
it since the comment says that that was already covered by previous
work.

The tests added by this patch show the broken behavior (the bug is
still open). I suspect the results returned from mergecopies() are not
expressive enough to fix this issue: it has a dict for copies to merge
with, but that can only give one more filename, but here we need two
(one for the path on the remote side and one for the path in the merge
base). I want to have it tested anyway since I'm about to refactor
mergecopies().

Differential Revision: https://phab.mercurial-scm.org/D6242

Minimal hgk check

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "hgk=" >> $HGRCPATH
  $ hg init repo
  $ cd repo
  $ echo a > a
  $ hg ci -Am adda
  adding a
  $ hg debug-cat-file commit 0
  tree a0c8bcbbb45c
  parent 000000000000
  author test 0 0
  revision 0
  branch default
  phase draft
  
  adda
  $ echo b > b
  $ hg ci -Am addb
  adding b
  $ hg log -T '{node}\n'
  102a90ea7b4a3361e4082ed620918c261189a36a
  07f4944404050f47db2e5c5071e0e84e7a27bba9

  $ hg debug-diff-tree 07f494440405 102a90ea7b4a
  :000000 100664 000000000000 1e88685f5dde N	b	b
  $ hg debug-diff-tree 07f494440405 102a90ea7b4a --patch
  diff --git a/b b/b
  new file mode 100644
  --- /dev/null
  +++ b/b
  @@ -0,0 +1,1 @@
  +b

Ensure that diff-tree output isn't affected by diffopts
  $ hg --config diff.noprefix=True debug-diff-tree 07f494440405 102a90ea7b4a
  :000000 100664 000000000000 1e88685f5dde N	b	b
  $ hg --config diff.noprefix=True debug-diff-tree --patch 07f494440405 102a90ea7b4a
  diff --git a/b b/b
  new file mode 100644
  --- /dev/null
  +++ b/b
  @@ -0,0 +1,1 @@
  +b

  $ cd ..