[PATCH V2] runtests: add 'diff' entry in json report

[Yuya Nishihara]

On Tue, 5 Jan 2016 13:33:23 -0800, Laurent Charignon wrote:
> # HG changeset patch
> # User Laurent Charignon <lcharignon at fb.com>
> # Date 1452029589 28800
> #      Tue Jan 05 13:33:09 2016 -0800
> # Node ID 77ef17fd99a8ece6f2d54648db2da0562136a5d7
> # Parent  b8405d739149cdd6d8d9bd5e3dd2ad8487b1f09a
> runtests: add 'diff' entry in json report
> 
> This patch adds to the json report the "diff" between expected and observed
> result. This diff can be useful for automatically filing bug report on failing
> tests.

Sounds good, pushed to the clowncopter, thanks.

>        "test-skip.t": {
>            "csys": "\s*[\d\.]{4,5}", ? (re)
>            "cuser": "\s*[\d\.]{4,5}", ? (re)
> +          "diff": "", 
>            "end": "\s*[\d\.]{4,5}", ? (re)
>            "result": "skip", ? (re)
>            "start": "\s*[\d\.]{4,5}", ? (re)

I've added " ? (re)" to all lines because it looks like necessary to work
around unstable JSON formatting.