diff --git a/release.nix b/release.nix
index 0a915db..734c3be 100644
--- a/release.nix
+++ b/release.nix
@@ -1,5 +1,6 @@
 { nixpkgs ? <nixpkgs>
 , system ? builtins.currentSystem
+, nix-processmgmt ? { outPath = ./.; rev = 1234; }
 }:
 
 let
@@ -13,7 +14,7 @@ rec {
 
   tests = {
     builds = import ./tests/builds.nix {
-      inherit pkgs;
+      inherit pkgs nix-processmgmt;
     };
 
     multi-process-images = import ./tests/multi-process-images.nix {
diff --git a/tests/builds.nix b/tests/builds.nix
index c7626ac..15e3b0d 100644
--- a/tests/builds.nix
+++ b/tests/builds.nix
@@ -1,8 +1,8 @@
-{pkgs ? import <nixpkgs> {}}:
+{ pkgs ? import <nixpkgs> {}
+, nix-processmgmt ? ./..
+}:
 
 let
-  nix-processmgmt = ./..;
-
   backends = [ "bsdrc" "cygrunsrv" "disnix" "docker" "launchd" "s6-rc" "supervisord" "systemd" "sysvinit" ];
 in
 pkgs.lib.genAttrs backends (backend: import "${nix-processmgmt}/nixproc/backends/${backend}/build-${backend}-env.nix" ({