tests: avoid side effects of $SHELL environment variable

Since non interactive shells don't generally set $SHELL,
its value is propagated through the tests and may cause issues;
for example if $SHELL implicitly adjusts $PATH when run.
Instead we set $SHELL to that determined by the posix-shell module,
and use that consistently for all test sub scripts,
including those created thorugh the `split --filter` command.

* tests/local.mk: Explicitly set $SHELL to $(PREFERABLY_POSIX_SHELL)
which defaults to $CONFIG_SHELL and thus usually /bin/sh.
* tests/envvar-check: Remove bash environment variables with
side effects, in case /bin/bash was selected for $SHELL.
* tests/misc/help-version.sh: Remove redundant initialization of $SHELL.
* tests/install/strip-program.sh: Use $SHELL for sub script.
* tests/misc/sort-compress-hang.sh: Likewise.
* tests/misc/sort-compress-proc.sh: Likewise.
* tests/misc/sort-compress.sh: Likewise.
* tests/misc/timeout-group.sh: Likewise.
* tests/rm/fail-eperm.xpl: Remove redundant elision of bash env vars.
* tests/misc/pwd-long.sh: Likewise.

1 files changed, 0 insertions, 6 deletions

diff --git a/tests/misc/help-version.sh b/tests/misc/help-version.sh
index e0dd721f9..78150374d 100755
--- a/tests/misc/help-version.sh
+++ b/tests/misc/help-version.sh
@@ -17,12 +17,6 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-# Ensure that $SHELL is set to *some* value and exported.
-# This is required for dircolors, which would fail e.g., when
-# invoked via debuild (which removes SHELL from the environment).
-test "x$SHELL" = x && SHELL=/bin/sh
-export SHELL
-
 . "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
 
 # Terminate any background processes