disko/tests: silence mdadm tests

Author: Mic92

lib/tests.nix

@@ -181,6 +181,9 @@ let
                   };
                   boot.zfs.devNodes = "/dev/disk/by-uuid"; # needed because /dev/disk/by-id is empty in qemu-vms
 
+                  # Silence mdadm warning about missing MAILADDR or PROGRAM
+                  boot.swraid.mdadmConf = "PROGRAM ${pkgs.coreutils}/bin/true";
+
                   # grub will install to these devices, we need to force those or we are offset by 1
                   # we use mkOveride 70, so that users can override this with mkForce in case they are testing grub mirrored boots
                   boot.loader.grub.devices = lib.mkOverride 70 testConfigInstall.boot.loader.grub.devices;