Re: [PATCH 2/6] iotests: Skip test 079 if it is not possible to create large files

[Thomas Huth <thuth@redhat.com>]

On 19/11/2019 18.50, Daniel P. Berrangé wrote:
> On Tue, Nov 19, 2019 at 06:38:20PM +0100, Philippe Mathieu-Daudé wrote:
>> On 11/19/19 6:34 PM, Thomas Huth wrote:
>>> On 19/11/2019 18.29, Philippe Mathieu-Daudé wrote:
>>>> On 11/19/19 6:08 PM, Thomas Huth wrote:
>>>>> Test 079 fails in the arm64, s390x and ppc64le LXD containers, which
>>>>> apparently do not allow large files to be created. Test 079 tries to
>>>>> create a 4G sparse file, so check first whether we can really create
>>>>> such files before executing the test.
>>>>>
>>>>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>>>>> ---
>>>>>    tests/qemu-iotests/079 | 6 ++++++
>>>>>    1 file changed, 6 insertions(+)
>>>>>
>>>>> diff --git a/tests/qemu-iotests/079 b/tests/qemu-iotests/079
>>>>> index 81f0c21f53..e9b81419b7 100755
>>>>> --- a/tests/qemu-iotests/079
>>>>> +++ b/tests/qemu-iotests/079
>>>>> @@ -39,6 +39,12 @@ trap "_cleanup; exit \$status" 0 1 2 3 15
>>>>>    _supported_fmt qcow2
>>>>>    _supported_proto file nfs
>>>>>    +# Some containers (e.g. non-x86 on Travis) do not allow large files
>>>>> +if ! truncate --size=4G "$TEST_IMG"; then
>>>>
>>>> Shouldn't we restrict that to Travis-CI by checking some environment var?
>>>
>>> I'd rather like to keep it independent from Travis environment
>>> variables, since somebody might want to run "make check" in other
>>> non-Travis containers or on weird filesystems, and then the test should
>>> ideally not fail, but simply skip, too.
>>
>> I see. But it would be bad if we stop catching normal bugs with this test
>> because we restricted it to contained environments.
>>
>> Maybe we can add a generic is_contained() routine that only checks for
>> TRAVIS env var, and people using other containers can expand it.
> 
> "is_contained" is still expressing the environment.
> 
> What we need is a way to express features, and be able to switch beteen
> autodetecting features & mandatory enablement.
> 
> eg
> 
>    if has_feature "large_file"
>    then
>        ...stuff using large files...
>    fi
> 
> The "has_feature" helper would by default call out to
> "has_feature_large_file" todo automatic probing so that things
> "just work" according to whatever env the tests are run inside.
> 
> There should, however, be a flag to "./check" which force enables
> the feature eg  "./check --require-feature large_file" will force
> execution and not attempt to probe for it.
> 
> We could have "--require-feature :all" to force enable all optional
> bits.
> 
> Any formal CI systems should use --require-feature to explicitly
> force testing of features that are expected to always work.
> 
> so Travis x86 would use "--require-feature large_large", but
> the arch64 version would not pass this flag and so do probing
> which will auto-skip.

Maybe a nice idea, but I think this is out of scope for this patch
series. We're using the "if ! truncate --size=4G" check in some other
tests already, so I'm not adding some new mechanism here.
If you want to see some more fine-grained control for the iotests,
please send some patches to rework these other tests first.

 Thomas