diff --git a/system/assertion.nix b/system/assertion.nix
new file mode 100644
index 00000000000..36eb36cb903
--- /dev/null
+++ b/system/assertion.nix
@@ -0,0 +1,25 @@
+{pkgs, config, ...}:
+
+let
+  inherit (pkgs.lib) mkOption filter concatMap concatStringsSep;
+  failed = map (x : x.message) (filter (x: ! x.assertion) config.assertions);
+in
+
+{
+
+  assertions = mkOption {
+    default = [];
+    example = [{ assertion = false; msg = "you can't enable this for that reason"; }];
+    merge = pkgs.lib.mergeListOption;
+    description = ''
+      Add something like this
+      assertions = mkAlways [ { assertion = false; message = "false should have been true"; } ];
+      to your upstart-job.
+    '';
+  };
+
+  environment = {
+    # extraPackages are evaluated always. Thus the assertions are checked as well. hacky!
+    extraPackages = if [] == failed then [] else throw "\n!! failed assertions: !!\n${concatStringsSep "\n" (map (x: "- ${x}") failed)}";
+  };
+}
diff --git a/system/options.nix b/system/options.nix
index 16269905633..5d39beb64b4 100644
--- a/system/options.nix
+++ b/system/options.nix
@@ -379,6 +379,9 @@ in
   };
 
   require = [
+
+    (import ../system/assertion.nix)
+
     # boot (is it the right place ?)
     (import ../system/kernel.nix)
     (import ../boot/boot-stage-2.nix)