tests: fix non POSIX constructs causing failures with dash

* tests/cp/no-ctx.sh: Scope of `var=val func` is inconsistent
across shells, so avoid that construct with functions.
* tests/df/no-mtab-status.sh: Likewise.
* tests/tail-2/inotify-race.sh: `read` needs an argument.
* tests/tail-2/inotify-race2.sh: Likewise.

4 files changed, 27 insertions, 22 deletions

diff --git a/tests/cp/no-ctx.sh b/tests/cp/no-ctx.sh
index 19d68b8ff..377d203b0 100755
--- a/tests/cp/no-ctx.sh
+++ b/tests/cp/no-ctx.sh
@@ -57,7 +57,8 @@ LD_PRELOAD=./k.so cp -a file_src file_dst || fail=1
 
 # ENODATA should give an immediate error when required to preserve ctx
 # This is debatable, and maybe we should not fail when no context available?
-LD_PRELOAD=./k.so returns_ 1 cp --preserve=context file_src file_dst || fail=1
+( export LD_PRELOAD=./k.so
+  returns_ 1 cp --preserve=context file_src file_dst ) || fail=1
 
 test -e preloaded || skip_ 'LD_PRELOAD interception failed'
 
diff --git a/tests/df/no-mtab-status.sh b/tests/df/no-mtab-status.sh
index 58a1852a2..41d1b521b 100755
--- a/tests/df/no-mtab-status.sh
+++ b/tests/df/no-mtab-status.sh
@@ -88,34 +88,38 @@ EOF
 gcc_shared_ k.c k.so \
   || framework_failure_ 'failed to build shared library'
 
+cleanup_() { unset LD_PRELOAD; }
+
+export LD_PRELOAD=./k.so
+
 # Test if LD_PRELOAD works:
-LD_PRELOAD=./k.so df
+df 2>/dev/null
 test -f x || skip_ "internal test failure: maybe LD_PRELOAD doesn't work?"
 
 # These tests are supposed to succeed:
-LD_PRELOAD=./k.so df '.' || fail=1
-LD_PRELOAD=./k.so df -i '.' || fail=1
-LD_PRELOAD=./k.so df -T '.' || fail=1
-LD_PRELOAD=./k.so df -Ti '.' || fail=1
-LD_PRELOAD=./k.so df --total '.' || fail=1
+df '.' || fail=1
+df -i '.' || fail=1
+df -T '.' || fail=1
+df -Ti '.' || fail=1
+df --total '.' || fail=1
 
 # These tests are supposed to fail:
-LD_PRELOAD=./k.so returns_ 1 df || fail=1
-LD_PRELOAD=./k.so returns_ 1 df -i || fail=1
-LD_PRELOAD=./k.so returns_ 1 df -T || fail=1
-LD_PRELOAD=./k.so returns_ 1 df -Ti || fail=1
-LD_PRELOAD=./k.so returns_ 1 df --total || fail=1
+returns_ 1 df || fail=1
+returns_ 1 df -i || fail=1
+returns_ 1 df -T || fail=1
+returns_ 1 df -Ti || fail=1
+returns_ 1 df --total || fail=1
 
-LD_PRELOAD=./k.so returns_ 1 df -a || fail=1
-LD_PRELOAD=./k.so returns_ 1 df -a '.' || fail=1
+returns_ 1 df -a || fail=1
+returns_ 1 df -a '.' || fail=1
 
-LD_PRELOAD=./k.so returns_ 1 df -l || fail=1
-LD_PRELOAD=./k.so returns_ 1 df -l '.' || fail=1
+returns_ 1 df -l || fail=1
+returns_ 1 df -l '.' || fail=1
 
-LD_PRELOAD=./k.so returns_ 1 df -t hello || fail=1
-LD_PRELOAD=./k.so returns_ 1 df -t hello '.' || fail=1
+returns_ 1 df -t hello || fail=1
+returns_ 1 df -t hello '.' || fail=1
 
-LD_PRELOAD=./k.so returns_ 1 df -x hello || fail=1
-LD_PRELOAD=./k.so returns_ 1 df -x hello '.' || fail=1
+returns_ 1 df -x hello || fail=1
+returns_ 1 df -x hello '.' || fail=1
 
 Exit $fail
diff --git a/tests/tail-2/inotify-race.sh b/tests/tail-2/inotify-race.sh
index 6e1a7fa40..4ce05083f 100755
--- a/tests/tail-2/inotify-race.sh
+++ b/tests/tail-2/inotify-race.sh
@@ -83,7 +83,7 @@ gdb -nx --batch-silent \
     --eval-command='quit'                          \
     tail < /dev/null > /dev/null 2>&1 & pid=$!
 
-tail --pid=$pid -f tail.out | (read; kill $pid)
+tail --pid=$pid -f tail.out | (read REPLY; kill $pid)
 
 # gdb has a bug in Debian's gdb-6.8-3 at least that causes it to not
 # cleanup and exit correctly when it receives a SIGTERM, but
diff --git a/tests/tail-2/inotify-race2.sh b/tests/tail-2/inotify-race2.sh
index 6d996eba7..1e01d5051 100755
--- a/tests/tail-2/inotify-race2.sh
+++ b/tests/tail-2/inotify-race2.sh
@@ -88,7 +88,7 @@ gdb -nx --batch-silent \
 # anything between coreutils 7.5 and 8.23 inclusive as
 # The old file descriptor (still held open by tail) was being fstat().
 
-tail --pid=$pid -f tail.out | (read; kill $pid)
+tail --pid=$pid -f tail.out | (read REPLY; kill $pid)
 
 # gdb has a bug in Debian's gdb-6.8-3 at least that causes it to not
 # cleanup and exit correctly when it receives a SIGTERM, but