add test for change #22776 ("open m" crashes Perl)

p4raw-link: @22776 on //depot/perl: e2ab214b14c9284fa9074628aa22936a93dab84f

p4raw-id: //depot/perl@22777

diff --git a/t/io/open.t b/t/io/open.t
index 82ac2f3..1871854 100755 (executable)
--- a/t/io/open.t
+++ b/t/io/open.t
@@ -12,7 +12,7 @@ use Config;
 $Is_VMS = $^O eq 'VMS';
 $Is_MacOS = $^O eq 'MacOS';
 
-plan tests => 105;
+plan tests => 106;
 
 my $Perl = which_perl();
 
@@ -306,3 +306,8 @@ SKIP: {
         'bad layer ":c" failure');
 }
 
+# [perl #28986] "open m" crashes Perl
+
+fresh_perl_like('open m', qr/^Search pattern not terminated at/,
+       { stderr => 1 }, 'open m test');
+