diff --git a/tests/mkfs-tests/031-zoned-bgt/test.sh b/tests/mkfs-tests/031-zoned-bgt/test.sh
index 91c107cd..e296c29b 100755
--- a/tests/mkfs-tests/031-zoned-bgt/test.sh
+++ b/tests/mkfs-tests/031-zoned-bgt/test.sh
@@ -4,37 +4,17 @@
 source "$TEST_TOP/common" || exit
 
 setup_root_helper
-prepare_test_dev
-
-nullb="$TEST_TOP/nullb"
 # Create one 128M device with 4M zones, 32 of them
-size=128
-zone=4
+setup_nullbdevs 1 128 4
 
-run_mayfail $SUDO_HELPER "$nullb" setup
-if [ $? != 0 ]; then
-	_not_run "cannot setup nullb environment for zoned devices"
-fi
+prepare_nullbdevs
 
-# Record any other pre-existing devices in case creation fails
-run_check $SUDO_HELPER "$nullb" ls
-
-# Last line has the name of the device node path
-out=$(run_check_stdout $SUDO_HELPER "$nullb" create -s "$size" -z "$zone")
-if [ $? != 0 ]; then
-	_fail "cannot create nullb zoned device $i"
-fi
-dev=$(echo "$out" | tail -n 1)
-name=$(basename "${dev}")
-
-run_check $SUDO_HELPER "$nullb" ls
-
-TEST_DEV="${dev}"
+TEST_DEV="${nullb_devs[1]}"
 # Use single as it's supported on more kernels
-run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -m single -d single -O block-group-tree "${dev}"
+run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -m single -d single -O block-group-tree "${TEST_DEV}"
 run_check_mount_test_dev
 run_check $SUDO_HELPER dd if=/dev/zero of="$TEST_MNT"/file bs=1M count=1
 run_check $SUDO_HELPER "$TOP/btrfs" filesystem usage -T "$TEST_MNT"
 run_check_umount_test_dev
 
-run_check $SUDO_HELPER "$nullb" rm "${name}"
+cleanup_nullbdevs