json.cjson: add a test case for more complex json object construction

vlib/json/cjson/cjson_test.v

@@ -6,3 +6,16 @@ fn test_object_with_null() {
 	root.add_item_to_object('age', cjson.create_null())
 	assert root.print_unformatted() == '{"name":"Andre","age":null}'
 }
+
+fn test_creating_complex_json() {
+	mut root := cjson.create_array()
+	root.add_item_to_array(cjson.create_string('user'))
+	mut obj := cjson.create_object()
+	obj.add_item_to_object('username', cjson.create_string('foo'))
+	obj.add_item_to_object('password', cjson.create_string('bar'))
+	root.add_item_to_array(obj)
+	result := root.print_unformatted()
+	println(result)
+
+	assert result == '["user",{"username":"foo","password":"bar"}]'
+}