--- /dev/null
+#!/bin/bash -e
+
+source $(dirname $0)/detect-build-env-vars.sh
+
+TMP=$(mktemp -d)
+trap "rm -fr $TMP" EXIT
+
+export PATH=$TMP:$PATH
+
+cat > $TMP/ceph-disk <<EOF
+echo '[{"partition":[{"type":"data","path":"/dev/foo/bar"}]}]'
+EOF
+chmod +x $TMP/ceph-disk
+
+cat > $TMP/df <<EOF
+echo Used
+echo $((2 * 1024 * 1024 * 1024))
+EOF
+chmod +x $TMP/df
+
+cat > $TMP/expected <<EOF
+{
+"band.storage.usage": 2
+}
+EOF
+export CEPH_FACTS_FILE=$TMP/facts
+$CEPH_ROOT/src/script/subman
+diff -u $CEPH_FACTS_FILE $TMP/expected