Re: [PATCH v2 12/17] kunit: tool: add Python wrappers for running KUnit tests

Brendan Higgins
2019-05-03T05:36:16Z

On Thu, May 2, 2019 at 6:45 PM Frank Rowand <frowand.list@gmail.com> wrote:
>
> On 5/2/19 4:45 PM, Brendan Higgins wrote:
> > On Thu, May 2, 2019 at 2:16 PM Frank Rowand <frowand.list@gmail.com> wrote:
> >>
> >> On 5/2/19 11:07 AM, Brendan Higgins wrote:
> >>> On Thu, May 2, 2019 at 4:02 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >>>>
> >>>> On Wed, May 01, 2019 at 04:01:21PM -0700, Brendan Higgins wrote:
> >>>>> From: Felix Guo <felixguoxiuping@gmail.com>
> >>>>>
> >>>>> The ultimate goal is to create minimal isolated test binaries; in the
> >>>>> meantime we are using UML to provide the infrastructure to run tests, so
> >>>>> define an abstract way to configure and run tests that allow us to
> >>>>> change the context in which tests are built without affecting the user.
> >>>>> This also makes pretty and dynamic error reporting, and a lot of other
> >>>>> nice features easier.
> >>>>>
> >>>>> kunit_config.py:
> >>>>> - parse .config and Kconfig files.
> >>>>>
> >>>>> kunit_kernel.py: provides helper functions to:
> >>>>> - configure the kernel using kunitconfig.
> >>>>> - build the kernel with the appropriate configuration.
> >>>>> - provide function to invoke the kernel and stream the output back.
> >>>>>
> >>>>> Signed-off-by: Felix Guo <felixguoxiuping@gmail.com>
> >>>>> Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
> >>>>
> >>>> Ah, here's probably my answer to my previous logging format question,
> >>>> right? What's the chance that these wrappers output stuff in a standard
> >>>> format that test-framework-tools can already parse? :)
> >
> > To be clear, the test-framework-tools format we are talking about is
> > TAP13[1], correct?
>
> I'm not sure what the test community prefers for a format. I'll let them
> jump in and debate that question.
>
>
> >
> > My understanding is that is what kselftest is being converted to use.
> >
> >>>
> >>> It should be pretty easy to do. I had some patches that pack up the
> >>> results into a serialized format for a presubmit service; it should be
> >>> pretty straightforward to take the same logic and just change the
> >>> output format.
> >>
> >> When examining and trying out the previous versions of the patch I found
> >> the wrappers useful to provide information about how to control and use
> >> the tests, but I had no interest in using the scripts as they do not
> >> fit in with my personal environment and workflow.
> >>
> >> In the previous versions of the patch, these helper scripts are optional,
> >> which is good for my use case. If the helper scripts are required to
> >
> > They are still optional.
> >
> >> get the data into the proper format then the scripts are not quite so
> >> optional, they become the expected environment. I think the proper
> >> format should exist without the helper scripts.
> >
> > That's a good point. A couple things,
> >
> > First off, supporting TAP13, either in the kernel or the wrapper
> > script is not hard, but I don't think that is the real issue that you
> > raise.
> >
> > If your only concern is that you will always be able to have human
> > readable KUnit results printed to the kernel log, that is a guarantee
> > I feel comfortable making. Beyond that, I think it is going to take a
> > long while before I would feel comfortable guaranteeing anything about
> > how will KUnit work, what kind of data it will want to expose, and how
> > it will be organized. I think the wrapper script provides a nice
> > facade that I can maintain, can mediate between the implementation
> > details and the user, and can mediate between the implementation
> > details and other pieces of software that might want to consume
> > results.
> >
> > [1] https://testanything.org/tap-version-13-specification.html
>
> My concern is based on a focus on my little part of the world
> (which in _previous_ versions of the patch series was the devicetree
> unittest.c tests being converted to use the kunit infrastructure).
> If I step back and think of the entire kernel globally I may end
> up with a different conclusion - but I'm going to remain myopic
> for this email.
>
> I want the test results to be usable by me and my fellow
> developers. I prefer that the test results be easily accessible
> (current printk() implementation means that kunit messages are
> just as accessible as the current unittest.c printk() output).
> If the printk() output needs to be filtered through a script
> to generate the actual test results then that is sub-optimal
> to me. It is one more step added to my workflow. And
> potentially with an embedded target a major pain to get a
> data file (the kernel log file) transferred from a target
> to my development host.

That's fair. If that is indeed your only concern, then I don't think
the wrapper script will ever be an issue for you. You will always be
able to execute a given test the old fashioned/manual way, and the
wrapper script only summarizes results, it does not change the
contents.

>
> I want a reported test failure to be easy to trace back to the
> point in the source where the failure is reported. With printk()
> the search is a simple grep for the failure message. If the
> failure message has been processed by a script, and then the
> failure reported to me in an email, then I may have to look
> at the script to reverse engineer how the original failure
> message was transformed into the message that was reported
> to me in the email. Then I search for the point in the
> source where the failure is reported. So a basic task has
> just become more difficult and time consuming.

That seems to be a valid concern. I would reiterate that you shouldn't
be concerned by any processing done by the wrapper script itself, but
the reality is that depending on what happens with automated
testing/presubmit/CI other people might end up parsing and
transforming test results - it might happen, it might not. I currently
have a CI system set up for KUnit on my public repo that I don't think
you would be offended by, but I don't know what we are going to do
when it comes time to integrate with existing upstream CI systems.

In anycase, I don't think that either sticking with or doing away with
the wrapper script is going to have any long term bearing on what
happens in this regard.

Cheers