diff --git a/test/nuts/z4.agent.trace.list.nut.ts b/test/nuts/z4.agent.trace.list.nut.ts
index 204afe89..1460220d 100644
--- a/test/nuts/z4.agent.trace.list.nut.ts
+++ b/test/nuts/z4.agent.trace.list.nut.ts
@@ -109,7 +109,7 @@ describe('agent trace list', function () {
 
   it('rejects an invalid --since value', () => {
     execCmd('agent trace list --since not-a-date --json', {
-      ensureExitCode: 1,
+      ensureExitCode: 'nonZero',
       cwd: session.project.dir,
     });
   });