Tests: add has() functions for feature testing.
Currently it just skips all tests if feature not found in nginx -V output.
diff --git a/smtp-greeting-delay.t b/smtp-greeting-delay.t
index 2c09401..a901432 100644
--- a/smtp-greeting-delay.t
+++ b/smtp-greeting-delay.t
@@ -7,7 +7,7 @@
use warnings;
use strict;
-use Test::More tests => 2;
+use Test::More;
use MIME::Base64;
use Socket qw/ CRLF /;
@@ -23,7 +23,8 @@
select STDERR; $| = 1;
select STDOUT; $| = 1;
-my $t = Test::Nginx->new()->write_file_expand('nginx.conf', <<'EOF')->run();
+my $t = Test::Nginx->new()->has('mail', plan => 2)
+ ->write_file_expand('nginx.conf', <<'EOF')->run();
master_process off;
daemon off;
