Re: [PATCH 07/22] tests/acceptance/virtiofs_submounts.py: evaluate string not length

["Alex Bennée" <alex.bennee@linaro.org>]

Max Reitz <mreitz@redhat.com> writes:

> On 09.02.21 12:24, Alex Bennée wrote:
>> 
>> Max Reitz <mreitz@redhat.com> writes:
>> 
>>> On 04.02.21 14:23, Alex Bennée wrote:
>>>>
>>>> Cleber Rosa <crosa@redhat.com> writes:
>>>>
>>>>> If the vmlinuz variable is set to anything that evaluates to True,
>>>>> then the respective arguments should be set.  If the variable contains
>>>>> an empty string, than it will evaluate to False, and the extra
>>>>> arguments will not be set.
>>>>>
>>>>> This keeps the same logic, but improves readability a bit.
>>>>>
>>>>> Signed-off-by: Cleber Rosa <crosa@redhat.com>
>>>>> ---
>>>>>    tests/acceptance/virtiofs_submounts.py | 2 +-
>>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/tests/acceptance/virtiofs_submounts.py b/tests/acceptance/virtiofs_submounts.py
>>>>> index f1b49f03bb..f25a386a19 100644
>>>>> --- a/tests/acceptance/virtiofs_submounts.py
>>>>> +++ b/tests/acceptance/virtiofs_submounts.py
>>>>> @@ -241,7 +241,7 @@ class VirtiofsSubmountsTest(BootLinux):
>>>>>    
>>>>>            super(VirtiofsSubmountsTest, self).setUp(pubkey)
>>>>>    
>>>>> -        if len(vmlinuz) > 0:
>>>>> +        if vmlinuz:
>>>>>                self.vm.add_args('-kernel', vmlinuz,
>>>>>                                 '-append', 'console=ttyS0 root=/dev/sda1')
>>>>
>>>> And this is were I gave up because I can't see how to run the test:
>>>>
>>>>     ./tests/venv/bin/avocado run ./tests/acceptance/virtiofs_submounts.py
>>>>     JOB ID     : b3d9bfcfcd603189a471bec7d770fca3b50a81ee
>>>>     JOB LOG    : /home/alex/avocado/job-results/job-2021-02-04T13.21-b3d9bfc/job.log
>>>>      (1/5) ./tests/acceptance/virtiofs_submounts.py:VirtiofsSubmountsTest.test_pre_virtiofsd_set_up: CANCEL: vmlinuz parameter not set; you must point it to a Linux kernel binary to test (to run this test with the on-image kernel, set it to an empty string) (0.00 s)
>>>>      (2/5) ./tests/acceptance/virtiofs_submounts.py:VirtiofsSubmountsTest.test_pre_launch_set_up: CANCEL: vmlinuz parameter not set; you must point it to a Linux kernel binary to test (to run this test with the on-image kernel, set it to an empty string) (0.00 s)
>>>>      (3/5) ./tests/acceptance/virtiofs_submounts.py:VirtiofsSubmountsTest.test_post_launch_set_up: CANCEL: vmlinuz parameter not set; you must point it to a Linux kernel binary
>>>>     to test (to run this test with the on-image kernel, set it to an empty string) (0.00 s)
>>>>      (4/5) ./tests/acceptance/virtiofs_submounts.py:VirtiofsSubmountsTest.test_post_mount_set_up: CANCEL: vmlinuz parameter not set; you must point it to a Linux kernel binary to test (to run this test with the on-image kernel, set it to an empty string) (0.00 s)
>>>>      (5/5) ./tests/acceptance/virtiofs_submounts.py:VirtiofsSubmountsTest.test_two_runs: CANCEL: vmlinuz parameter not set; you must point it to a Linux kernel binary to test (to run this test with the on-image kernel, set it to an empty string) (0.00 s)
>>>>     RESULTS    : PASS 0 | ERROR 0 | FAIL 0 | SKIP 0 | WARN 0 | INTERRUPT 0 | CANCEL 5
>>>>     JOB TIME   : 0.56 s
>>>>
>>>> Given the test seems to make assumptions about an environment being
>>>> setup for it I think we need some documentation somewhere about what
>>>> those pre-requisites are.
>>>
>>> I find the cancel message pretty clear, but then again it was me who
>>> wrote it...
>>>
>>> Either you point the vmlinuz parameter to some Linux kernel you built
>>> yourself, or you set it to the empty string to just use the kernel
>>> that’s part of the image.  Setting Avocado parameters is done via -p,
>>> i.e. “-p key=value”.  So in this case
>>> “-p vmlinuz=/path/to/linux/build/arch/x86/boot/bzImage”, or
>>> “-p vmlinuz=''”.
>>>
>>> Ideally, vmlinuz='' would be the default, but there’s a problem with
>>> that: I submitted this test along with the patches that added the
>>> required feature to the Linux kernel, so at that point that feature was
>>> not part of Linux.  That’s why you generally have to point it to a Linux
>>> kernel binary you built yourself that has this feature (5.10 does).
>> 
>> This is where it deviates from the rest of the check-acceptance tests.
>> Generally I don't have to worry about finding the right image myself.
>
> Yes, but there’s nothing I can do apart from just not having the test as 
> part of qemu, which I don’t find better than to just cancel it when not 
> run with the necessary parameters.

No I agree having the tests is useful.

>
> Or, well, I could let the test download and compile the Linux sources, 
> but I don’t think that’s a viable alternative.

There has been discussion before but I agree it's not viable given the
compile times for such things.

>> At the least it would be worth pointing to a part of our docs on how
>> to build such an image.
>
> Well, I could perhaps come up with a comprehensive kernel configuration 
> that works, but I really don’t think that’s valuable for people who just 
> want to run the acceptance tests and don’t care about this test in 
> particular.  I just don’t think they’re actually going to build a Linux 
> kernel just for it.

Sure - but I was trying to review the series and as part of my review I
generally like to run the things I review. Hence why I stopped as I
couldn't get things running.

> (Alternatively, I could just build a Linux kernel here on my machine, 
> upload the binary and point to it somewhere, e.g. in the cancel message. 
>   That would be OK for me, and perhaps something I could imagine someone 
> might actually use.)

I've actually done this with some Xen patches I'm working on at the
moment. I'll probably decorate the test with:

  @skipUnless(os.getenv('AVOCADO_ALLOW_UNTRUSTED_CODE'), 'untrusted code')

with a comment explaining what's waiting to be upstreamed. Once there
are upstream binaries I plan on transitioning the test to those.

> I’d rather just wait until the test image contains a kernel that’s 
> sufficiently new (should be the case once Fedora 34 is out), so we can 
> make -p vmlinuz='' the default.  Until then I personally find it 
> completely reasonable to have this test just be cancelled.
>
> Max


-- 
Alex Bennée