[U-Boot] [PATCH] Implement pytest-based test infrastructure

[Simon Glass]

Hi Stephen,

On 22 November 2015 at 10:30, Stephen Warren <swarren at wwwdotorg.org> wrote:
> On 11/21/2015 09:49 AM, Simon Glass wrote:
>> Hi Stephen,
>>
>> On 19 November 2015 at 12:09, Stephen Warren <swarren at wwwdotorg.org> wrote:
>>>
>>> On 11/19/2015 10:00 AM, Stephen Warren wrote:
>>>>
>>>> On 11/19/2015 07:45 AM, Simon Glass wrote:
>>>>>
>>>>> Hi Stephen,
>>>>>
>>>>> On 14 November 2015 at 23:53, Stephen Warren <swarren at wwwdotorg.org>
>>>>> wrote:
>>>>>>
>>>>>> This tool aims to test U-Boot by executing U-Boot shell commands
>>>>>> using the
>>>>>> console interface. A single top-level script exists to execute or attach
>>>>>> to the U-Boot console, run the entire script of tests against it, and
>>>>>> summarize the results. Advantages of this approach are:
>>>>>>
>>>>>> - Testing is performed in the same way a user or script would interact
>>>>>>    with U-Boot; there can be no disconnect.
>>>>>> - There is no need to write or embed test-related code into U-Boot
>>>>>> itself.
>>>>>>    It is asserted that writing test-related code in Python is simpler
>>>>>> and
>>>>>>    more flexible that writing it all in C.
>>>>>> - It is reasonably simple to interact with U-Boot in this way.
>>>>>>
>>>>>> A few simple tests are provided as examples. Soon, we should convert as
>>>>>> many as possible of the other tests in test/* and test/cmd_ut.c too.
>>>>>
>>>>>
>>>>> It's great to see this and thank you for putting in the effort!
>>>>>
>>>>> It looks like a good way of doing functional tests. I still see a role
>>>>> for unit tests and things like test/dm. But if we can arrange to call
>>>>> all U-Boot tests (unit and functional) from one 'test.py' command that
>>>>> would be a win.
>>>>>
>>>>> I'll look more when I can get it to work - see below.
>>>
>>> ...
>>>>
>>>> made it print a message about checking the docs for missing
>>>> requirements. I can probably patch the top-level test.py to do the same.
>>>
>>>
>>> I've pushed such a patch to:
>>>
>>> git://github.com/swarren/u-boot.git tegra_dev
>>> (the separate pytests branch has now been deleted)
>>>
>>> There are also a variety of other patches there related to this testing infra-structure. I guess I'll hold off sending them to the list until there's been some general feedback on the patches I've already posted, but feel free to pull the branch down and play with it. Note that it's likely to get rebased as I work.
>>
>> OK I got it working thank you. It is horribly slow though - do you
>> know what is holding it up? For me to takes 12 seconds to run the
>> (very basic) tests.
>
> It looks like pexpect includes a default delay to simulate human
> interaction. If you edit test/py/uboot_console_base.py ensure_spawned()
> and add the following somewhere soon after the assignment to self.p:
>
>             self.p.delaybeforesend = 0
>
> ... that will more than halve the execution time. (8.3 -> 3.5s on my
> 5-year-old laptop).
>
> That said, even your 12s or my 8.3s doesn't seem like a bad price to pay
> for some easy-to-use automated testing.

Sure, but my reference is to the difference between a native C test
and this framework. As we add more and more tests the overhead will be
significant. If it takes 8 seconds to run the current (fairly trivial)
tests, it might take a minute to run a larger suite, and to me that is
too long (e.g. to bisect for a failing commit).

I wonder what is causing the delay?

>
>> Also please see dm_test_usb_tree() which uses a console buffer to
>> check command output.
>
> OK, I'll take a look.
>
>> I wonder if we should use something like that
>> for simple unit tests, and use python for the more complicated
>> functional tests?
>
> I'm not sure that's a good idea; it'd be best to settle on a single way
> of executing tests so that (a) people don't have to run/implement
> different kinds of tests in different ways (b) we can leverage test code
> across as many tests as possible.
>
> (Well, doing unit tests and system level tests differently might be
> necessary since one calls functions and the other uses the shell "user
> interface", but having multiple ways of doing e.g. system tests doesn't
> seem like a good idea.)

As you found with some of the tests, it is convenient/necessary to be
able to call U-Boot C functions in some tests. So I don't see this as
a one-size-fits-all solution.

I think it is perfectly reasonable for the python framework to run the
existing C tests - there is no need to rewrite them in Python. Also
for the driver model tests - we can just run the tests from some sort
of python wrapper and get the best of both worlds, right?

Please don't take this to indicate any lack of enthusiasm for what you
are doing - it's a great development and I'm sure it will help a lot!
We really need to unify all the tests so we can run them all in one
step.

I just think we should aim to have the automated tests run in a few
seconds (let's say 5-10 at the outside). We need to make sure that the
python framework will allow this even when running thousands of tests.

Regards,
Simon