pointer check in unit tests

[Stephan Bergmann]

On 04/11/2020 08:26, Miklos Vajna wrote:
> If a never-nullptr pointer is returned, it would be really useful to
> somehow state that in the function's signature. Are you aware of any way
> to do that? There is C's __attribute__((nonnull)), but it only works on
> function parameters, I think.

see "not_null" at 
<https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines>