{lib, ...}: {
  imports = [./../../mailsystem];
  config = {
    virtualisation.memorySize = 1024;
    mailsystem = {
      enable = true;
      certificateScheme = "selfsigned";
    };

    # Prevent tests deadlocking on DNS requests which will never succeed.
    services.rspamd.locals."options.inc".text = ''
      dns {
        nameservers = ["127.0.0.1"];
        timeout = 0.0s;
        retransmits = 0;
      }
    '';

    # Enable more verbose logging (required for, e.g., sieve testing)
    services.dovecot2.extraConfig = lib.mkAfter ''
      mail_debug = yes
      auth_debug = yes
      verbose_ssl = yes
    '';
  };
}