cppunit tests fail in arm64 clang (gnu++17) build

[jimklimov]

https://travis-ci.org/github/jimklimov/nut/jobs/745390423 :

FAIL: cppunittest

=================
D: Getting test suite...
D: Preparing test runner...
D: Setting test runner outputter...
D: Launching the test run...

..F.F

nutclienttest.cpp:61:Assertion

Test name: NutClientTest::test_stringset_to_strarr
assertion failed

- Expression: arr!=NULL
- stringset_to_strarr(...) result is null

nutclienttest.cpp:88:Assertion

Test name: NutClientTest::test_stringvector_to_strarr
assertion failed

- Expression: arr!=NULL
- stringvector_to_strarr(...) result is null

Failures !!!

Run: 3   Failure total: 2   Failures: 2   Errors: 0

D: Got to the end of test suite with code '0'

FAIL cppunittest (exit status: 1)

[jimklimov]

Recurring with recent QEMU aarch64 builds on the new NUT CI farm as well (with clang, but seems not with gcc):

[2021-10-22T08:21:57.832Z] FAIL: cppunittest
[2021-10-22T08:21:57.832Z] =================
[2021-10-22T08:21:57.832Z] 
[2021-10-22T08:21:57.832Z] D: Getting test suite...
[2021-10-22T08:21:57.832Z] D: Preparing test runner...
[2021-10-22T08:21:57.832Z] D: Setting test runner outputter...
[2021-10-22T08:21:57.832Z] D: Launching the test run...
[2021-10-22T08:21:57.832Z] ..F.F.......F
[2021-10-22T08:21:57.832Z] 
[2021-10-22T08:21:57.832Z] nutclienttest.cpp:110:Assertion
[2021-10-22T08:21:57.832Z] Test name: nut::NutClientTest::test_stringset_to_strarr
[2021-10-22T08:21:57.832Z] assertion failed
[2021-10-22T08:21:57.832Z] - Expression: arr != nullptr
[2021-10-22T08:21:57.832Z] - stringset_to_strarr(...) result is null
[2021-10-22T08:21:57.832Z] 
[2021-10-22T08:21:57.832Z] nutclienttest.cpp:137:Assertion
[2021-10-22T08:21:57.832Z] Test name: nut::NutClientTest::test_stringvector_to_strarr
[2021-10-22T08:21:57.832Z] assertion failed
[2021-10-22T08:21:57.832Z] - Expression: arr != nullptr
[2021-10-22T08:21:57.832Z] - stringvector_to_strarr(...) result is null
[2021-10-22T08:21:57.832Z] 
[2021-10-22T08:21:57.832Z] nutclienttest.cpp:235:Assertion
[2021-10-22T08:21:57.832Z] Test name: nut::NutClientTest::test_nutclientstub_dev
[2021-10-22T08:21:57.832Z] assertion failed
[2021-10-22T08:21:57.832Z] - Expression: values.size() == 1
[2021-10-22T08:21:57.832Z] - Failed stub tcp client: mono wrong values number
[2021-10-22T08:21:57.832Z] 
[2021-10-22T08:21:57.832Z] Failures !!!
[2021-10-22T08:21:57.832Z] Run: 10   Failure total: 3   Failures: 3   Errors: 0
[2021-10-22T08:21:57.832Z] D: Got to the end of test suite with code 'false'
[2021-10-22T08:21:57.832Z] FAIL cppunittest (exit status: 1)
[2021-10-22T08:21:57.832Z] 

Can't quickly find the links, but it is possible similar issue was seen on other (QEMU-backed) platforms of the new NUT CI farm, and cppunit tests might have been disabled on those build agents by the announced capability labels.

[jimklimov]

Seems to be same issue as #1126 and should get "solved" by PR #1162

Root cause so far seems to be some quirk in CppUnit itself, failing assertions regardless of arguments on some build environments.