How to unit-test a phobos module?

[Q. Schroll]

When trying to unit-test an unchanged phobos module from 
phobos/master, I get errors such as

     module core.lifetime import copyEmplace not found

and template instantiation errors. What is the correct arguments 
to pass to (r)dmd? I know it worked for me some years ago, but 
somehow, it doesn't work now.

I've looked at [1], [2], [3] which didn't work (maybe outdated?). 
How do you do it and what am I doing wrong?

My setup:
* A fresh DMD installed a few minutes ago.
* Clone of my Phobos fork with up-to-date changes from 
dlang/phobos/master.

In the clone's folder, ~/dlang/phobos, I tried the following 
commands:

     $ dmd -main -unittest -version=StdUnittest -I. -run 
std/<module>.d

and

     $ rdmd -main -unittest -version=StdUnittest -I. std/<module>.d

I have the feeling I'm missing something quite obvious.

[1] 
https://wiki.dlang.org/Contributing_to_Phobos#Test_a_single_Phobos_module
[2] 
https://wiki.dlang.org/Building_under_Windows#Building_Phobos_2
[3] https://github.com/dlang/phobos/blob/master/CONTRIBUTING.md