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/h08m091kj3p0a2sq3li29amgzwy5skj4-nixos-test-driver-postgis.drv
  /nix/store/q78559sw4ffpnw7slkwdap2h3a48wf8p-vm-test-run-postgis.drv