How can one reliably run unittests

[James Blachly]

On 9/2/21 7:00 PM, Steven Schveighoffer wrote:
> What I was saying is, you have a library, you built it without -unittest 
> (on its own build line, or just use dub because it does the right 
> thing), and then you build your main application with -unittest, linking 
> in the already-built library (or its object files). The runtime runs all 
> unittests it finds, and so it's running just the modules that were built 
> with the -unittest flag.
>

Steve:

Sorry to reply a few days late and in the middle of a gargantuan thread, 
but I wanted some clarification from you on dub just doing the right 
thing --

Let's suppose I maintain a library L (written in D; has unit tests). 
Suppose further I have client program P, which uses L.

As far as I can tell, if P's dubfile includes library L, and the user 
execeutes `dub test` then the unit tests from the library L as well as 
program P are built and executed.

We had to wrap our library's unittests in `debug(library_unittest)` to 
escape this behavior.

Can you provide some clarity because it sounds like you are saying dub 
will build P's unit tests, but not library L's? Not at all my 
experience, unless it was updated recently.