diff --git a/tools/client-plugins/browser-scripts/test-evaluator.ts b/tools/client-plugins/browser-scripts/test-evaluator.ts
index 839fb42488a..1508457a3bf 100644
--- a/tools/client-plugins/browser-scripts/test-evaluator.ts
+++ b/tools/client-plugins/browser-scripts/test-evaluator.ts
@@ -132,7 +132,7 @@ ctx.onmessage = async (e: TestEvaluatorEvent) => {
 __utils.flushLogs();
 __userCodeWasExecuted = true;
 __utils.toggleProxyLogger(true);
-${e.data.testString}`)) as unknown;
+(async () => {${e.data.testString}})()`)) as unknown;
     } catch (err) {
       if (__userCodeWasExecuted) {
         // rethrow error, since test failed.