these 6 derivations will be built:
  /nix/store/dq3lgknyaczab0vbf37n0dyymy111w4i-nixos-system-server-test.drv
  /nix/store/qb2h1bvmzw3y5qrz6y54d17qryw7yy4d-closure-info.drv
  /nix/store/wwl8ya9x92s6z7mawz0jbrb0ydjjhqk8-run-nixos-vm.drv
  /nix/store/w8af3rjvxyraq9y3wyx7jv26s95qn12q-nixos-vm.drv
  /nix/store/bvyrvn191wdfq0c5lwggfax8h4s5jjxc-nixos-test-driver-pg_repack.drv
  /nix/store/kfrwwlrx0bgjkpl37m9s10fv0rvqwkvc-vm-test-run-pg_repack.drv