Hi zimoun,  

  
What about using guix to build like:
  

  
guix build -f guix.scm
  

  
I believe that is how that file is meant to work.
  

  
I’m not sure it entirely answers your question on how to test but maybe something like this would work:
  

  
guix environment -L . --ad-hoc emacs emacs-guix -- emacs -Q
  

  
What do you think?
  

  
- John