How can one reliably run unittests

[jfondren]

On Wednesday, 25 August 2021 at 21:05:42 UTC, Paul Backus wrote:
> If we had something like -main=ifMissing that added an empty 
> main function only if the modules being compiled didn't already 
> have one, then it would be possible to unit-test any D module 
> with a command line like
>
>     dmd -i -unittest -main=ifMissing -run mymodule.d
>
> Being able to use the same command for everything makes 
> automation much easier--you can write it in a makefile rule, 
> put it in a script, etc.

Although at this point, the -main=ifMissing functionality should 
just be part of -unittest