Re: [PATCH 1/2] kselftests: timers: Make set-timer-lat fail more gracefully for !CAP_WAKE_ALARM

From: Michael Ellerman <mpe@ellerman.id.au>
To: John Stultz <john.stultz@linaro.org>
Cc: Prarit Bhargava <prarit@redhat.com>,
	Tyler Baker <tyler.baker@linaro.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Shuah Khan <shuahkh@osg.samsung.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Richard Cochran <richardcochran@gmail.com>,
	Robert Collins <robertc@robertcollins.net>
Subject: Re: [PATCH 1/2] kselftests: timers: Make set-timer-lat fail more gracefully for !CAP_WAKE_ALARM
Date: Wed, 08 Apr 2015 14:03:11 +1000	[thread overview]
Message-ID: <1428465791.29968.5.camel@ellerman.id.au> (raw)
In-Reply-To: <CALAqxLUbhaq4+KTrjj=_FG7xq-yzME44noXhgn1ND0C-6HBdOw@mail.gmail.com>

On Thu, 2015-04-02 at 11:02 -0700, John Stultz wrote:
> On Thu, Apr 2, 2015 at 3:18 AM, Prarit Bhargava <prarit@redhat.com> wrote:
> > On 03/26/2015 01:33 PM, Tyler Baker wrote:
> >> I realize this may be a good amount of work, so I'd like to help out.
> >> Perhaps working John to convert his timer tests to use TAP output
> >> would be a good starting point?
> >
> > John, I could probably do that for you.  I'm always willing to give it a shot.
> 
> I took a quick look into it, since I'm definitely interested in
> improving output formatting, but man, TAP is a fairly ugly output
> format if you ask me.
> 
> It only has binary "ok" or "not ok" (why not "fail", or something else
> that's exclusively grep-able, I don't know). So I'm not sure if cases
> where functionality is unsupported should be a pass or fail.
> 
> Most problematically: It seems to want enumeration in the test output
> (so test 2 needs to print: "ok 2 Test complete") which means either
> there needs to be a wrapper that does the TAP output knowing which
> test of N its currently running, or the test number needs to be
> submitted as an runtime argument to the test, and the test then has to
> add it to its output line.

Yeah TAP is horrible, for the reasons you describe.

I *think* in practice most tools will handle just "ok" / "not ok" without the
tests being numbered, but I don't know that for sure.

For the powerpc tests I'm using "subunit v1" [1], which is basically just:
  - "^success: <test name>"
  - "^failure: <test name>"

See: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/powerpc/subunit.h

So I can do eg:

$ cd tools/testing/selftests/powerpc
$ make run_tests 2>&1 | subunit-1to2 | subunit-stats --no-passthrough
Total tests:      35
Passed tests:     31
Failed tests:      0
Skipped tests:     4
Seen tags: git_version:v4.0-rc7-0-gf22e6e8

But unfortunately TAP has a lot more traction with tools.

It wouldn't be too hard to convert the subunit stream into TAP I think, but for
some reason no one seems to have written that. Maybe we should, I just haven't
had time to do it.

cheers

[1]: https://github.com/testing-cabal/subunit/blob/master/README#L343