Hi,

I'm on commit db194f714a8beb155c508c06e346c7c2322e7053. Running tests 
with fish as shell always results in failure at test 
tests/guix-environment.sh. Seems like problem is with difference in 
`set` output format.

`set` command in fish outputs environmental variables in format:
VAR1 VAL1
VAR2 VAL2

tests/guix-environment.sh expects format:
VAR1=VAL1
VAR2=VAL2

Thanks,
Mikhail