diff --git a/tests/bonsai/hru.sh b/tests/bonsai/hru.sh
new file mode 100755
index 0000000..fd59e69
--- /dev/null
+++ b/tests/bonsai/hru.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+# Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
+# SPDX-License-Identifier: FSFAP
+#
+# Copying and distribution of this file, with or without modification, are
+# permitted in any medium without royalty provided the copyright notice and this
+# notice are preserved.  This file is offered as-is, without any warranty.
+
+. tests/bonsai/aliases
+
+alias strcmp="$BIN/strcmp"
+alias rpn="$BIN/rpn"
+
+strcmp "$(printf '1234\n' | hru)" '1.2 kB'
+strcmp "$(printf '0\n' | hru)" '0 B'
+
+# doesn’t currently work but would be useful for testing for regressions
+#n=1
+#while "$BIN/true"; do
+#	n="$(rpn "$n" 10 ×)"
+#
+#	printf '%s\n' "$n" | hru || break
+#done
+#printf 'integer limit: ~%s\n' "$(rpn "$n" 10 ÷)"
+
+! printf '%s\n' '-1' | hru