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

6 files changed, 20 insertions, 29 deletions

diff --git a/tests/misc/date-next-dow b/tests/misc/date-next-dow
index e61d405ad..fda213bd6 100755
--- a/tests/misc/date-next-dow
+++ b/tests/misc/date-next-dow
@@ -73,6 +73,6 @@ my $fail = run_tests ($ME, $prog, \@Tests, $save_temps, $verbose);
 # Skip the test if the starting and stopping day numbers differ.
 my @d_post = localtime (time);
 $d_post[7] == $d[7]
-  or (warn "$ME: test straddled a day boundary; skipped"), exit 77;
+  or CuSkip::skip "$ME: test straddled a day boundary; skipped";
 
 exit $fail;
diff --git a/tests/misc/ls-misc b/tests/misc/ls-misc
index 7c3bc7894..8b356d4ae 100755
--- a/tests/misc/ls-misc
+++ b/tests/misc/ls-misc
@@ -17,7 +17,7 @@
 
 use strict;
 
-(my $program_name = $0) =~ s|.*/||;
+(my $ME = $0) =~ s|.*/||;
 my $prog = 'ls';
 
 # Turn off localization of executable's output.
@@ -61,8 +61,8 @@ sub setuid_setup()
            mkdir sticky && chmod +t sticky  && $test -k sticky &&
            mkdir owt    && chmod +t,o+w owt && $test -k owt &&
            mkdir owr    && chmod o+w owr)) == 0
-             or (warn "$program_name: cannot create setuid/setgid/sticky files,"
-                 . "so can't run this test\n"), exit 77;
+             or CuSkip::skip "$ME: cannot create setuid/setgid/sticky files,"
+                 . "so can't run this test\n";
 }
 
 sub mk_file(@)
@@ -285,7 +285,7 @@ my $save_temps = $ENV{SAVE_TEMPS};
 my $verbose = $ENV{VERBOSE};
 
 setuid_setup;
-my $fail = run_tests ($program_name, $prog, \@Tests, $save_temps, $verbose);
+my $fail = run_tests ($ME, $prog, \@Tests, $save_temps, $verbose);
 $fail
   and exit 1;
 
@@ -296,5 +296,5 @@ $env =~ s/\';.*//sm;
 $ENV{LS_COLORS} = $env;
 
 setuid_setup;
-$fail = run_tests ($program_name, $prog, \@Tests, $save_temps, $verbose);
+$fail = run_tests ($ME, $prog, \@Tests, $save_temps, $verbose);
 exit $fail;
diff --git a/tests/misc/md5sum-newline b/tests/misc/md5sum-newline
index 3b6d2f46a..efd9fd3a1 100755
--- a/tests/misc/md5sum-newline
+++ b/tests/misc/md5sum-newline
@@ -18,7 +18,7 @@
 
 use strict;
 
-(my $program_name = $0) =~ s|.*/||;
+(my $ME = $0) =~ s|.*/||;
 
 # Turn off localization of executable's output.
 @ENV{qw(LANGUAGE LANG LC_ALL)} = ('C') x 3;
@@ -26,7 +26,7 @@ use strict;
 # See if we can create a file name that contains a newline.
 # Use system, since Perl doesn't let you do this with "open".
 system ('touch', "a\nb") == 0
-  or (warn "$0: failed to create newline-containing file name\n"), exit 77;
+  or CuSkip::skip "$ME: failed to create newline-containing file name\n";
 
 my $degenerate = "d41d8cd98f00b204e9800998ecf8427e";
 my $t = '--text';
@@ -40,5 +40,5 @@ my $save_temps = $ENV{DEBUG};
 my $verbose = $ENV{VERBOSE};
 
 my $prog = 'md5sum';
-my $fail = run_tests ($program_name, $prog, \@Tests, $save_temps, $verbose);
+my $fail = run_tests ($ME, $prog, \@Tests, $save_temps, $verbose);
 exit $fail;
diff --git a/tests/misc/pwd-long b/tests/misc/pwd-long
index 7fa95abc0..3a5147d76 100755
--- a/tests/misc/pwd-long
+++ b/tests/misc/pwd-long
@@ -30,7 +30,7 @@ export ARGV_0
 
 # Don't use CuTmpdir here, since File::Temp's use of rmtree can't
 # remove the deep tree we create.
-$PERL -Tw -- - <<\EOF
+$PERL -Tw -I"$abs_srcdir" -MCuSkip -- - <<\EOF
 
 # Show that pwd works even when the length of the resulting
 # directory name is longer than PATH_MAX.
@@ -77,12 +77,9 @@ substr ($expected, 0, 1) = '';
 my $i = 0;
 do
   {
-    if (!mkdir $z, 0700)
-      {
-        warn "$ME: skipping this test; cannot create long directory name "
-          . "at depth $i: $!\n";
-        exit 77;
-      }
+    mkdir $z, 0700
+      or CuSkip::skip "$ME: skipping this test; cannot create long "
+        . "directory name at depth $i: $!\n";
     chdir $z
   }
 until (++$i == $n);
@@ -91,12 +88,9 @@ my $abs_top_builddir = $ENV{abs_top_builddir};
 $abs_top_builddir
   or die "$ME: envvar abs_top_builddir not defined\n";
 my $build_src_dir = "$abs_top_builddir/src";
-if ($build_src_dir !~ m!^([-+.:/\w]+)$!)
-  {
-    warn "$ME: skipping this test; odd build source directory name:\n"
-      . "$build_src_dir\n";
-    exit 77;
-  }
+$build_src_dir =~ m!^([-+.:/\w]+)$!
+  or CuSkip::skip "$ME: skipping this test; odd build source directory name:\n"
+    . "$build_src_dir\n";
 $build_src_dir = $1;
 
 my $pwd_binary = "$build_src_dir/pwd";
diff --git a/tests/misc/tty-eof b/tests/misc/tty-eof
index 14910dcfc..23cb4d564 100755
--- a/tests/misc/tty-eof
+++ b/tests/misc/tty-eof
@@ -25,8 +25,8 @@ use strict;
 # Some older versions of Expect.pm (e.g. 1.07) lack the log_user method,
 # so check for that, too.
 eval { require Expect; Expect->require_version('1.11') };
-$@ and (warn "$ME: this script requires Perl's Expect package >=1.11\n"),
-  exit 77;
+$@
+  and CuSkip::skip "$ME: this script requires Perl's Expect package >=1.11\n";
 
 {
   my $fail = 0;
diff --git a/tests/misc/uniq b/tests/misc/uniq
index 1a260e498..99aa8edfe 100755
--- a/tests/misc/uniq
+++ b/tests/misc/uniq
@@ -82,11 +82,8 @@ sub add_z_variants($)
 
 # I've only ever triggered the problem in a non-C locale.
 my $locale = $ENV{LOCALE_FR};
-if (! defined $locale || $locale eq 'none')
-  {
-    warn "$prog: skipping this test -- no appropriate locale\n";
-    exit 77;
-  }
+! defined $locale || $locale eq 'none'
+  and CuSkip::skip "$prog: skipping this test -- no appropriate locale\n";
 
 # See if isblank returns true for nbsp.
 my $x = `env printf '\xa0'| LC_ALL=$locale tr '[:blank:]' x`;