diff --git a/tests/extern.nix b/tests/extern.nix
index f29acc2..32af471 100644
--- a/tests/extern.nix
+++ b/tests/extern.nix
@@ -249,5 +249,12 @@ import <nixpkgs/nixos/tests/make-test.nix> {
 
       };
 
+      subtest "no warnings or errors", sub {
+          $server->fail("journalctl -u postfix | grep -i error");
+          $server->fail("journalctl -u postfix | grep -i warning");
+          $server->fail("journalctl -u dovecot2 | grep -i error");
+          $server->fail("journalctl -u dovecot2 | grep -i warning");
+      };
+
     '';
 }