tests: factor out the perl-requiring code in many test scripts

* tests/require-perl: New file.
* tests/Makefile.am (EXTRA_DIST): Add require-perl.
* tests/dd/skip-seek: Use it, and remove manual tests.
* tests/du/files0-from: Likewise.
* tests/ls/nameless-uid: Likewise.
* tests/misc/base64: Likewise.
* tests/misc/basename: Likewise.
* tests/misc/cut: Likewise.
* tests/misc/date: Likewise.
* tests/misc/dircolors: Likewise.
* tests/misc/dirname: Likewise.
* tests/misc/expand: Likewise.
* tests/misc/expr: Likewise.
* tests/misc/factor: Likewise.
* tests/misc/fmt: Likewise.
* tests/misc/fold: Likewise.
* tests/misc/head-elide-tail: Likewise.
* tests/misc/ls-misc: Likewise.
* tests/misc/md5sum: Likewise.
* tests/misc/md5sum-newline: Likewise.
* tests/misc/mktemp: Likewise.
* tests/misc/od: Likewise.
* tests/misc/paste-no-nl: Likewise.
* tests/misc/pr: Likewise.
* tests/misc/pwd-long: Likewise.
* tests/misc/seq: Likewise.
* tests/misc/sha1sum: Likewise.
* tests/misc/sha1sum-vec: Likewise.
* tests/misc/sha224sum: Likewise.
* tests/misc/sha256sum: Likewise.
* tests/misc/sha384sum: Likewise.
* tests/misc/sha512sum: Likewise.
* tests/misc/sort-merge: Likewise.
* tests/misc/stat-printf: Likewise.
* tests/misc/sum: Likewise.
* tests/misc/sum-sysv: Likewise.
* tests/misc/test-diag: Likewise.
* tests/misc/tsort: Likewise.
* tests/misc/tty-eof: Likewise.
* tests/misc/unexpand: Likewise.
* tests/misc/wc-files0-from: Likewise.
* tests/misc/xstrtol: Likewise.
* tests/mv/i-1: Likewise.
* tests/rm/empty-name: Likewise.
* tests/rm/fail-eperm: Likewise.
* tests/rm/unreadable: Likewise.

(EXTRA_DIST): *do* require require-perl as a stand-alone, 'source'able script.

3 files changed, 3 insertions, 12 deletions

diff --git a/tests/rm/empty-name b/tests/rm/empty-name
index 1384a2fd1..a250985c9 100755
--- a/tests/rm/empty-name
+++ b/tests/rm/empty-name
@@ -21,11 +21,8 @@
 # actually remove files with names of entries in the current directory
 # but relative to `/' rather than relative to the current directory.
 
-: ${PERL=perl}
 : ${srcdir=.}
-
-$PERL -e 'use warnings;' > /dev/null 2>&1 ||
-  skip_test_ "configure didn't find a usable version of Perl"
+. $srcdir/../require-perl
 
 me=`echo $0|sed 's,.*/,,'`
 exec $PERL -w -I$srcdir/.. -MCoreutils -M"CuTmpdir qw($me)" -- - << \EOF
diff --git a/tests/rm/fail-eperm b/tests/rm/fail-eperm
index c619574ce..4abc9dec6 100755
--- a/tests/rm/fail-eperm
+++ b/tests/rm/fail-eperm
@@ -29,11 +29,8 @@ fi
 
 PRIV_CHECK_ARG=require-non-root . $srcdir/../priv-check
 
-: ${PERL=perl}
 : ${srcdir=.}
-
-$PERL -e 1 > /dev/null 2>&1 ||
-  skip_test_ "configure didn't find a usable version of Perl"
+. $srcdir/../require-perl
 
 ARGV_0=$0
 export ARGV_0
diff --git a/tests/rm/unreadable b/tests/rm/unreadable
index 05024c2dc..4fb40235c 100755
--- a/tests/rm/unreadable
+++ b/tests/rm/unreadable
@@ -16,11 +16,8 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-: ${PERL=perl}
 : ${srcdir=.}
-
-$PERL -e 'use warnings;' > /dev/null 2>&1 ||
-  skip_test_ "configure didn't find a usable version of Perl"
+. $srcdir/../require-perl
 
 me=`echo $0|sed 's,.*/,,'`
 exec $PERL -w -I$srcdir/.. -MCoreutils -M"CuTmpdir qw($me)" -- - << \EOF