tests: write skip explanation from perl scripts also to outer stderr

* tests/CuSkip.pm (skip): New file/module/function, to help
the perl test scripts "skip" a test consistently, emitting
a diagnostic both into the log file and into the outermost
stderr stream that is more likely to be seen by a human.
* tests/check.mk (TESTS_ENVIRONMENT): Add -MCuSkip.
* tests/misc/date-next-dow: Use CuSkip::skip in place of warn+exit-77.
* tests/misc/tty-eof: Likewise.
* tests/misc/uniq: Likewise.
* tests/rm/fail-eperm: Likewise.
* tests/misc/md5sum-newline: Likewise.  Also, s/program_name/ME/.
* tests/misc/ls-misc (setuid_setup, main): Likewise.
* tests/misc/pwd-long: Likewise, and add -I"$abs_srcdir" -MCuSkip
to the $PERL invocation command.
Inspired by a request from Bruno Haible regarding misc/tty-eof:
http://debbugs.gnu.org/8570

1 files changed, 39 insertions, 0 deletions

diff --git a/tests/CuSkip.pm b/tests/CuSkip.pm
new file mode 100644
index 000000000..6f5ec4803
--- /dev/null
+++ b/tests/CuSkip.pm
@@ -0,0 +1,39 @@
+package CuSkip;
+# Skip a test: emit diag to log and to stderr, and exit 77
+
+# Copyright (C) 2011 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+use strict;
+use warnings;
+
+our $ME = $0 || "<???>";
+
+# Emit a diagnostic both to stderr and to $stderr_fileno_.
+# FIXME: don't hard-code that value (9), since it's already defined in init.cfg.
+sub skip ($)
+{
+  my ($msg) = @_;
+  my $stderr_fileno_ = 9;
+  warn $msg;
+  open FH, ">&$stderr_fileno_"
+    or warn "$ME: failed to dup stderr\n";
+  print FH $msg;
+  close FH
+    or warn "$ME: failed to close FD $stderr_fileno_\n";
+  exit 77;
+}
+
+1;