Re: [PATCH] tests: don't make tail's pipe-f2 test take the full 10 seconds

[Pádraig Brady]

On 10/28/2011 05:08 PM, Jim Meyering wrote:
> I noticed that on a very fast system, the tail-2/pipe-f2 test
> was nearly the last one to complete.  Turns out it was taking
> 10 seconds, when in fact it needs more than 1 only very rarely.
> Now, it usually completes in less than 1/3 of a second:
> 
>>From 7b901da8c364e8880bc8798f949630c04723ec7b Mon Sep 17 00:00:00 2001
> From: Jim Meyering <address@hidden>
> Date: Fri, 28 Oct 2011 18:06:44 +0200
> Subject: [PATCH] tests: don't make tail's pipe-f2 test take the full 10
>  seconds
> 
> * tests/tail-2/pipe-f2: Don't always wait 10 seconds.
> Before, this test would always wait 10 seconds.
> Now, it stops early when it detects that tail -f has written output.
> BTW, the race condition that prompted changing the timeout from 1 second
> to 10 was that tail -f could be killed by the timeout before producing
> any output.
> ---
>  tests/tail-2/pipe-f2 |   15 +++++++++++++--
>  1 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/tail-2/pipe-f2 b/tests/tail-2/pipe-f2
> index f1ae470..d0d08c9 100755
> --- a/tests/tail-2/pipe-f2
> +++ b/tests/tail-2/pipe-f2
> @@ -24,9 +24,20 @@ mkfifo_or_skip_ fifo
>  echo 1 > fifo &
>  echo 1 > exp || framework_failure_
> 
> -timeout 10 tail -f fifo > out
> -test $? = 124 || fail=1
> +timeout 10 tail -f fifo > out & pid=$!
> +
> +check_tail_output()
> +{
> +  local n_sec="$1"
> +  test -s out || { sleep $n_sec; return 1; }
> +}
> +
> +# Wait 6.3s for tail to write something.
> +tail_re='inaccessible' retry_delay_ check_tail_output .1 7 || fail=1

You don't need the tail_re here.
Otherwise it looks good.

cheers,
Pádraig.