tests: pwd-long: diagnose failure earlier

Without this change, we'd get use-of-uninit value warnings
and harder-to-diagnose failure down the road.
* tests/misc/pwd-long (normalize_to_cwd_relative): Diagnose stat
failure.  This failed on AIX 6.1 and 7.1.  Reported by Bruno Haible.

1 files changed, 2 insertions, 0 deletions

diff --git a/tests/misc/pwd-long b/tests/misc/pwd-long
index 3a5147d76..e31845796 100755
--- a/tests/misc/pwd-long
+++ b/tests/misc/pwd-long
@@ -50,6 +50,8 @@ sub normalize_to_cwd_relative ($$$)
         and die "$ME: $dir does not contain old CWD\n";
       my $dir_prefix = $slash ? substr ($dir, 0, $slash) : '/';
       my ($d, $i) = (stat $dir_prefix)[0, 1];
+      defined $d && defined $i
+        or die "$ME: $dir_prefix: stat failed: $!\n";
       $d eq $dev && $i eq $ino
         and return substr $dir, $slash + 1;
     }