diff --git a/tests/common.convert b/tests/common.convert
index 1b5217c3..0d22949c 100644
--- a/tests/common.convert
+++ b/tests/common.convert
@@ -130,17 +130,18 @@ convert_test_prep_fs() {
 # generate md5 checksums of files on $TEST_MNT
 # $1: path where the checksums will be stored
 convert_test_gen_checksums() {
-	local CHECKSUMTMP
-	CHECKSUMTMP="$1"
+	_assert_path "$1"
 
 	run_check $SUDO_HELPER dd if=/dev/zero of=$TEST_MNT/test bs=$nodesize \
 		count=1 >/dev/null 2>&1
-	run_check_stdout $SUDO_HELPER find $TEST_MNT -type f ! -name 'image' -exec md5sum {} \+ > "$CHECKSUMTMP"
+	run_check_stdout $SUDO_HELPER find $TEST_MNT -type f ! -name 'image' -exec md5sum {} \+ > "$1"
 }
 # list $TEST_MNT data set file permissions.
 # $1: path where the permissions will be stored
 convert_test_perm() {
 	local PERMTMP
+
+	_assert_path "$1"
 	PERMTMP="$1"
 	FILES_LIST=$(mktemp --tmpdir btrfs-progs-convert.fileslistXXXXXX)
 
@@ -185,6 +186,7 @@ convert_test_post_check_permissions() {
 	local EXT_PERMTMP
 	local BTRFS_PERMTMP
 
+	_assert_path "$1"
 	EXT_PERMTMP="$1"
 	BTRFS_PERMTMP=$(mktemp --tmpdir btrfs-progs-convert.permXXXXXX)
 	convert_test_perm "$BTRFS_PERMTMP"
@@ -207,6 +209,7 @@ convert_test_post_check_acl() {
 	local EXT_ACLTMP
 	local BTRFS_ACLTMP
 
+	_assert_path "$1"
 	EXT_ACLTMP="$1"
 	BTRFS_ACLTMP=$(mktemp --tmpdir btrfs-progs-convert.aclsXXXXXXX)
 	convert_test_acl "$BTRFS_ACLTMP"
@@ -226,10 +229,8 @@ convert_test_post_check_acl() {
 
 # post conversion checks, verify md5sums
 convert_test_post_check_checksums() {
-	local CHECKSUMTMP
-
-	CHECKSUMTMP="$1"
-	run_check_stdout $SUDO_HELPER md5sum -c "$CHECKSUMTMP" |
+	_assert_path "$1"
+	run_check_stdout $SUDO_HELPER md5sum -c "$1" |
 		grep -q 'FAILED' && _fail "file validation failed"
 }
 
@@ -238,17 +239,14 @@ convert_test_post_check_checksums() {
 # $2: file with permissions.
 # $3: file with acl entries.
 convert_test_post_checks_all() {
-	local CHECKSUMTMP
-	local EXT_PERMTMP
-	local EXT_ACLTMP
+	_assert_path "$1"
+	_assert_path "$2"
+	_assert_path "$3"
 
-	CHECKSUMTMP="$1"
-	EXT_PERMTMP="$2"
-	EXT_ACLTMP="$3"
 	run_check_mount_test_dev
-	convert_test_post_check_checksums "$CHECKSUMTMP"
-	convert_test_post_check_permissions "$EXT_PERMTMP"
-	convert_test_post_check_acl "$EXT_ACLTMP"
+	convert_test_post_check_checksums "$1"
+	convert_test_post_check_permissions "$2"
+	convert_test_post_check_acl "$3"
 	run_check_umount_test_dev
 }