diff --git a/test/frontend.test.js b/test/frontend.test.js
index 2400c9da2..6ec2f85a1 100644
--- a/test/frontend.test.js
+++ b/test/frontend.test.js
@@ -93,6 +93,7 @@ describe('Frontend', () => {
         const mockWSClient = {
             implementation: {
                 close: jest.fn(),
+                send: jest.fn(),
             },
             events: {},
         };