Further exclude tests that require unzip when not installed

Change-Id: I6a1f2ef6eb778e445c361d562186ad65dd58cbb3
diff --git a/t/script/config.t b/t/script/config.t
index 9ca2a36..5ec57cb 100644
--- a/t/script/config.t
+++ b/t/script/config.t
@@ -8,11 +8,16 @@
 use Test::More;
 use Test::Output qw/combined_from/;
 use Data::Dumper;
+use KorAP::XML::Archive;
 
 if ($ENV{SKIP_SCRIPT}) {
   plan skip_all => 'Skip script tests';
 };
 
+unless (KorAP::XML::Archive::test_unzip) {
+  plan skip_all => 'unzip not found';
+};
+
 my $f = dirname(__FILE__);
 
 my ($fh, $cfg_file) = tempfile();