diff --git a/tests/21_json_pretty.claro b/tests/21_json_pretty.claro
new file mode 100644
index 0000000..0074eb8
--- /dev/null
+++ b/tests/21_json_pretty.claro
@@ -0,0 +1,10 @@
+SET obj TO MAP
+PUT obj KEY "a" VALUE 1
+PUT obj KEY "b" VALUE 2
+SET arr TO LIST
+ADD 10 TO arr
+ADD 20 TO arr
+PUT obj KEY "nums" VALUE arr
+
+MAKE JSON PRETTY obj AS out
+SAY out