diff --git a/src/lib/utils/stateMapper.test.ts b/src/lib/utils/stateMapper.test.ts
index 50ca8a1..e723330 100644
--- a/src/lib/utils/stateMapper.test.ts
+++ b/src/lib/utils/stateMapper.test.ts
@@ -267,10 +267,10 @@ describe("stateMapper", () => {
     });
 
     it("returns null for result with unknown subtype", () => {
-      const message: ClaudeStreamMessage = {
+      const message = {
         type: "result",
         subtype: "unknown_type",
-      };
+      } as unknown as ClaudeStreamMessage;
       expect(mapMessageToState(message)).toBeNull();
     });