I tried disabling the tests in a package override in my GUIX_PACKAGE_PATH:

--8<---------------cut here---------------start------------->8---
    (arguments
     `(...
       #:tests? #f 
       ...
--8<---------------cut here---------------end--------------->8---
       
or with

--8<---------------cut here---------------start------------->8---
    (arguments
     `(...
       #:phases
       (modify-phases %standard-phases
         (delete 'check)
       ...
--8<---------------cut here---------------end--------------->8---

Surprisingly, it did not work.
I wonder if my override is taken into account.
I also wonder how to disable individual tests.
I haven't spent much time on it as I am rather busy these days, sorry :p

-- 
Pierre Neidhardt