Run unit tests with C++ too

[Ferruh Yigit]

On 5/1/2024 3:14 PM, Mattias Rönnblom wrote:
> On 2024-05-01 11:10, Ferruh Yigit wrote:
>> On 4/30/2024 9:57 PM, Patrick Robb wrote:
>>>
>>>
>>> On Tue, Apr 30, 2024 at 4:13 PM Mattias Rönnblom <hofors at lysator.liu.se
>>> <mailto:hofors at lysator.liu.se>> wrote:
>>>
>>>      On 2024-04-30 15:52, Patrick Robb wrote:
>>>      >
>>>      >
>>>      > On Sun, Apr 28, 2024 at 3:46 AM Mattias Rönnblom
>>>      <hofors at lysator.liu.se <mailto:hofors at lysator.liu.se>
>>>      > <mailto:hofors at lysator.liu.se <mailto:hofors at lysator.liu.se>>>
>>> wrote:
>>>      >
>>>      >     It would be great if the unit test suite (app/test/*) was
>>>      compiled (and
>>>      >     run) using a C++ (C++11) compiler as well. At least, if
>>> such is
>>>      >     available.
>>>      >
>>>      >
>>>      > Sure, the UNH Lab can try this.
>>>      >
>>>      >
>>>      >     With the current state of affairs, header file macros or
>>>      functions are
>>>      >     not verified to be functional (or even valid) C++.
>>>      >
>>>      >     "C is a subset of C++", which was never true, is becoming
>>> less and
>>>      >     less so.
>>>      >
>>>      >     If all unit tests aren't valid C++, maybe one could start
>>> with
>>>      an "opt
>>>      >     in" model.
>>>      >
>>>      >
>>>      > Okay, so basically run the fast-test suite, record all that don't
>>>      pass,
>>>      > submit a bugzilla ticket stating which unit tests are not
>>> valid on a
>>>      > certain c++ compiler, then bring CI Testing online using the
>>> valid
>>>      > subset of fast-tests. This should work.
>>>      >
>>>
>>>      Sounds good.
>>>
>>>      Just to be clear: the above includes extending the DPDK build
>>> system to
>>>      build the app/test/dpdk-test binary in two versions: one C and
>>> one C++,
>>>      so that anyone can run the C++ tests locally as well. Correct?
>>>
>>>
>>> Okay, so now I am understanding this is not yet available. When I
>>> responded this morning I was figuring that c++ compiler support was
>>> available and I simply wasn't aware, and that we could quite easily set
>>> cc={some c++ compiler}, meson would pick it up, and we would be able to
>>> build DPDK and then run unit tests in this manner in CI testing.
>>>
>>> I didn't mean to suggest we would submit patches extending the build
>>> system to this end. That's probably a little out of scope for what we
>>> try to accomplish at the Community Lab.
>>>
>>> But if the aforementioned build system support is added, of course we
>>> are willing to add that as a build environment for unit tests and report
>>> those respective results.
>>>   
>>
>> Does it have to be 'app/test/dpdk-test', why not build examples with C++?
>>
> 
> The unit tests have the ability to test DPDK, which is exactly what we
> want to do here. Such testing isn't limited to "compiles yes/no", but to
> detect run-time (behavioral) issues, and properly report them.
> 
> This is especially important for cases where there is code only
> exercised in C++ translation units (i.e., in #ifdef __cplusplus).
> 

And Bruce highlighted that compile check is already covered.

Than I guess this work needs to be done in two steps,
1. Enable building dpdk-test (or all applications) with C++ in build
system. And fix possible issues.

2. Enable in dpdk-test C++ build and run in CI.

We need a volunteer for 1. before asking CI lab for 2.