➜ sudo nixos-rebuild test --fast
building the system configuration...
these derivations will be built:
  /nix/store/qwi0bvwdak9zjaxng7713iwq7m74cflv-etc.drv
  /nix/store/r821k3s4h771q1691gb2sy1vyi5kd4ph-nixos-system-entadono-19.03.173322.67135fbcc5d.drv
building '/nix/store/qwi0bvwdak9zjaxng7713iwq7m74cflv-etc.drv'...
duplicate entry openal/alsoft.conf -> /nix/store/8m345v86s7hyq50n9qdd726hnlsi6xib-alsoft.conf
mismatched duplicate entry /nix/store/45w43bjacy8s2bi9gx8jdzmvs8msmcn6-etc-alsoft.conf <-> /nix/store/8m345v86s7hyq50n9qdd726hnlsi6xib-alsoft.conf
builder for '/nix/store/qwi0bvwdak9zjaxng7713iwq7m74cflv-etc.drv' failed with exit code 1
cannot build derivation '/nix/store/r821k3s4h771q1691gb2sy1vyi5kd4ph-nixos-system-entadono-19.03.173322.67135fbcc5d.drv': 1 dependencies couldn't be built
error: build of '/nix/store/r821k3s4h771q1691gb2sy1vyi5kd4ph-nixos-system-entadono-19.03.173322.67135fbcc5d.drv' failed