Run unit tests with C++ too

[Mattias Rönnblom]

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).

> Examples source codes can be installed with existing build support.
> Later we can build these examples with C++, this doesn't require any
> update in build system.
>