How to unit-test a phobos module?

[Q. Schroll]

On Wednesday, 25 November 2020 at 21:57:12 UTC, H. S. Teoh wrote:
> On Wed, Nov 25, 2020 at 09:49:12PM +0000, Paul Backus via 
> Digitalmars-d-learn wrote:
>> On Wednesday, 25 November 2020 at 21:16:06 UTC, Q. Schroll 
>> wrote:
>> > On Wednesday, 25 November 2020 at 21:11:24 UTC, Paul Backus 
>> > wrote:
>> > > On Wednesday, 25 November 2020 at 20:58:20 UTC, Q. Schroll 
>> > > wrote:
>> > > > My setup:
>> > > > * A fresh DMD installed a few minutes ago.
>> > > > * Clone of my Phobos fork with up-to-date changes from
>> > > > dlang/phobos/master.
>> > > 
>> > > Do you have clones of dmd and druntime too?
>> > 
>> > Why would I need those? I haven't needed them back then.
>> 
>> copyEmplace isn't in druntime 2.094.2.
>
> My guess is that the problem is caused by trying to compile 
> Phobos with a compiler that uses an incompatible version of 
> druntime.

One of the issues is, I don't know what DRuntime really is. As 
far as I understand on the surface-level, it's functionality one 
would expect to be implemented by the compiler, but actually 
implemented in plain D code. A low-level Phobos if you want. So 
I'm a little confused why there's even a need for it to be 
"built". Isn't it "just code" like Phobos?

I'm increasingly frustrated because, honestly, it seems I don't 
know enough about the build processes or build tools used. The 
Wiki expects Digital Mars make to be there, also says explicitly 
not to confuse it with GNU make, but in my DMD folder there is 
none. Since it's a plain install, I suspect the Wiki is outdated. 
How am I expected to figure things out? It seems like everyone 
else knows how to do it, just I'm too stupid.

> *ME* Why would I need those? I haven't needed them back then.

I wrote that not saying "do the work for me, guys" but "please 
tell me what changed".