Hi,

The ‘make check-system TESTS=nix’ doesn't succeeded with patch applied
on 13c4a377f5a2e1240790679f3d5643385b6d7635:
--8<---------------cut here---------------start------------->8---
building of '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv': woken up
substitution of '/nix/store/30xf8m13vrk3n8hfi9q4mkjmxvhqi4g4-guix-test': goal destroyed
building of '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv': all outputs substituted (maybe)
building of '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv': all inputs realised
building path '/nix/store/30xf8m13vrk3n8hfi9q4mkjmxvhqi4g4-guix-test'
added input paths 
building of '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv': woken up
building of '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv': trying to build
locking path '/nix/store/30xf8m13vrk3n8hfi9q4mkjmxvhqi4g4-guix-test'
lock acquired on '/nix/store/30xf8m13vrk3n8hfi9q4mkjmxvhqi4g4-guix-test.lock'
removing invalid path '/nix/store/30xf8m13vrk3n8hfi9q4mkjmxvhqi4g4-guix-test'
starting build hook '/gnu/store/0xgj4bz1ac973pw9wr8rhg3z1qc0phf8-nix-2.3.10/libexec/nix/build-remote'
cannot find machines file '/etc/nix/machines'
got 0 remote builders
hook reply is 'decline-permanently'
killing process 186
found build user 'nixbld01'
found build user 'nixbld02'
found build user 'nixbld03'
found build user 'nixbld04'
found build user 'nixbld05'
found build user 'nixbld06'
found build user 'nixbld07'
found build user 'nixbld08'
found build user 'nixbld09'
found build user 'nixbld10'
trying user 'nixbld01'
killing all processes running under uid '989'
setting up chroot environment in '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv.chroot'
executing builder '/gnu/store/pwcp239kjf7lnj5i4lkdzcfcxwcfyk72-bash-minimal-5.0.16/bin/bash'
bind mounting '/tmp/nix-build-guix-test.drv-0' to '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv.chroot/build'
bind mounting '/dev/full' to '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv.chroot/dev/full'
bind mounting '/dev/null' to '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv.chroot/dev/null'
bind mounting '/dev/random' to '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv.chroot/dev/random'
bind mounting '/dev/tty' to '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv.chroot/dev/tty'
bind mounting '/dev/urandom' to '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv.chroot/dev/urandom'
bind mounting '/dev/zero' to '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv.chroot/dev/zero'
closing leaked FD 3
closing leaked FD 4
closing leaked FD 5
closing leaked FD 6
closing leaked FD 7
closing leaked FD 8
closing leaked FD 9
closing leaked FD 10
closing leaked FD 11
closing leaked FD 12
closing leaked FD 13
building '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv'...
while setting up the build environment: executing '/gnu/store/pwcp239kjf7lnj5i4lkdzcfcxwcfyk72-bash-minimal-5.0.16/bin/bash': No such file or directory
building of '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv': got EOF
building of '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv': woken up
building of '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv': build done
killing process 190
builder process for '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv' finished
killing all processes running under uid '989'
builder for '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv' failed with exit code 1
lock released on '/nix/store/30xf8m13vrk3n8hfi9q4mkjmxvhqi4g4-guix-test.lock'
building of '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv': done
building of '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv': goal destroyed
error: build of '/nix/store/nvx13nribwnd47hs6frbq61vlq2n3nzh-guix-test.drv' failed
QEMU runs as PID 14
connected to QEMU's monitor
read QEMU monitor prompt
connected to guest REPL
%%%% Starting test nix  (Writing full log to "nix.log")
marionette is ready
/gnu/store/xmnqlhxlbywkp688im5kpwr6q4mbil4g-nix-test-builder:1: FAIL Nix daemon running
# of expected passes      1
# of unexpected failures  1
note: keeping build directory `/tmp/guix-build-nix-test.drv-0'
builder for `/gnu/store/bl5gryai81zxmdhs6zzkb17nbpypyhsw-nix-test.drv' failed with exit code 1
build of /gnu/store/bl5gryai81zxmdhs6zzkb17nbpypyhsw-nix-test.drv failed
View build log at '/var/log/guix/drvs/bl/5gryai81zxmdhs6zzkb17nbpypyhsw-nix-test.drv.bz2'.
guix build: error: build of `/gnu/store/bl5gryai81zxmdhs6zzkb17nbpypyhsw-nix-test.drv' failed
make: *** [Makefile:6894: check-system] Error 1
--8<---------------cut here---------------end--------------->8---

It doens't fail without the patch.  Could I ask what issue the
build-sandbox-paths introduce for you?  Also it would be helpful if you
provide terminal output with an error you occurred.

Thanks,
Oleg.