diff --git a/tests/serde.rs b/tests/serde.rs
index d2026506..8ee666c4 100644
--- a/tests/serde.rs
+++ b/tests/serde.rs
@@ -2,7 +2,7 @@
 
 use rhai::{
     serde::{from_dynamic, to_dynamic},
-    Dynamic, Engine, EvalAltResult, INT,
+    Dynamic, Engine, EvalAltResult, ImmutableString, INT,
 };
 use serde::{Deserialize, Serialize};