On Thu, Dec 01 2016, ng0 wrote 
> I tried that before (though I did just think it was wrong) and 
> now I get the same message as yesterday:
>
> ...
> 
> In gnu/services/cuirass.scm: 
>   81: 1 [cuirass-shepherd-service #] 
> In unknown file: 
>    ?: 0 [string=? "" ((# # # # ...))]
>
> ERROR: In procedure string=?: ERROR: In procedure string=: Wrong 
> type argument in position 2 (expecting string): (((#:name . 
> "guix") (#:url . "git://git.savannah.gnu.org/guix.git") 
> (#:load-path . ".") (#:file . 
> "/.../cuirass/tests/gnu-system.scm") (#:proc . hydra-jobs) 
> (#:arguments (subset . "hello")) (#:branch . "master")))

It looks like cuirass is expecting the specifications to be a 
string, not a list. I don't know anything about cuirass, so I 
can't help you to configure the cuirass-service.

Looking at the source, specifications has a comment ";string
(file-name)". It looks like the "specifications" field of the
configuration is just equivalent to the --specifications argument to the
cuirass command, if that helps at all.