RFR(S) : 8243432 : use reproducible random in :vmTestbase_vm_defmeth

[Igor Ignatyev]

> On Apr 30, 2020, at 8:44 PM, David Holmes <david.holmes at oracle.com> wrote:
> 
> On 1/05/2020 1:38 pm, Igor Ignatyev wrote:
>> Hi David,
>> one reason is to remove redundant code, vmTestbase have several classes which provide means to specify seed, and it might have made sense in old test-harness where each testlist/testgroup might have been seen as a separate product, it's not really a case anymore.
>> another is to unify how we specify a seed, so it would be easier to have a seed value "stable" for a build/CI run, which will help to compare results of "randomness" tests from different runs w/o their re-execution, right now if you have such test failing let's say on windows-x64 and linux-x64, you can't tell if it's platform specific or not until you rerun on one of the platforms w/ the seed from another. and from that perspective, 8243432  and other subtasks of 8241623 are just preparation step, yet w/ an extra value of their own.
> 
> So can't we program the obtaining of the seed into the existing framework?
that would mean we will still have multiple ways to set the seed and we will need to update them all if some changes in the way we set up seed is needed.

> What if you just switch the default seed from 0 (random) to the mystical 42?
that would make these test fully/more deterministic and can potentially impair test coverage.

-- Igor
> 
> David
> 
>> Thanks,
>> -- Igor
>>  
>>> On Apr 30, 2020, at 7:48 PM, David Holmes <david.holmes at oracle.com> wrote:
>>> 
>>> Hi Igor,
>>> 
>>> On 1/05/2020 3:23 am, Igor Ignatyev wrote:
>>>> http://cr.openjdk.java.net/~iignatyev/8243432/webrev.00
>>>>> 22 lines changed: 3 ins; 12 del; 7 mod;
>>>> Hi all,
>>>> could you please review this small patch?
>>>> from JBS:
>>>>> this subtask is to use j.t.l.Utils.getRandomInstance() as a random number generator, where applicable, in : vmTestbase_vm_defmeth test group and marking the tests which make use of "randomness" with a proper k/w.
>>> 
>>> Sorry I don't like this change at all. The code already supports using a deterministic seed so why not just set it?
>>> 
>>> Thanks,
>>> David
>>> 
>>>> testing: : vmTestbase_vm_defmeth test group
>>>> JBS: https://bugs.openjdk.java.net/browse/JDK-8243432
>>>> webrevs:
>>>> - code changes: http://cr.openjdk.java.net/~iignatyev//8243432/webrev.00.code
>>>>> 16 lines changed: 1 ins; 12 del; 3 mod;
>>>> - adding k/w: http://cr.openjdk.java.net/~iignatyev//8243432/webrev.00.kw
>>>>> 2 lines changed: 2 ins; 0 del; 0 mod;
>>>> - full: http://cr.openjdk.java.net/~iignatyev//8243432/webrev.00
>>>>> 22 lines changed: 3 ins; 12 del; 7 mod;
>>>> Thanks,
>>>> -- Igor