test: use an explicit no-op for file truncation

test/units/testsuite-04.sh

@@ -6,14 +6,14 @@ set -o pipefail
 
 # Skip empty lines
 ID=$(journalctl --new-id128 | sed -n 2p)
->/expected
+: >/expected
 printf $'\n\n\n' | systemd-cat -t "$ID" --level-prefix false
 journalctl --sync
 journalctl -b -o cat -t "$ID" >/output
 cmp /expected /output
 
 ID=$(journalctl --new-id128 | sed -n 2p)
->/expected
+: >/expected
 printf $'<5>\n<6>\n<7>\n' | systemd-cat -t "$ID" --level-prefix true
 journalctl --sync
 journalctl -b -o cat -t "$ID" >/output

test/units/testsuite-17.sh

@@ -3,7 +3,7 @@
 set -eux
 set -o pipefail
 
->/failed
+: >/failed
 
 for t in "${0%.sh}".*.sh; do
     echo "Running $t"; ./"$t"

test/units/testsuite-22.03.sh

@@ -161,7 +161,7 @@ test -f /tmp/F/ro-fs/foo
 grep -q 'truncating is not allowed' /tmp/F/ro-fs/foo
 
 # Trying to change the perms should fail.
->/tmp/F/rw-fs/foo
+: >/tmp/F/rw-fs/foo
 systemd-tmpfiles --create - <<EOF && { echo 'unexpected success'; exit 1; }
 F     /tmp/F/ro-fs/foo    0666 - - - -
 EOF

test/units/testsuite-22.sh

@@ -3,7 +3,7 @@
 set -eux
 set -o pipefail
 
->/failed
+: >/failed
 
 for t in "${0%.sh}".*.sh; do
     echo "Running $t"; ./"$t"

test/units/testsuite-53.sh

@@ -2,7 +2,7 @@
 set -eux
 set -o pipefail
 
->/failed
+: >/failed
 
 # Reset host date to current time, 3 days in the past.
 date -s "-3 days"