From 16b0768a93414f02e5d2402d3944f3edbb63bf2c Mon Sep 17 00:00:00 2001
From: Richard Hansen <rhansen@rhansen.org>
Date: Sun, 11 Oct 2020 21:48:40 -0400
Subject: [PATCH] tests: Fix unchainable `helper.waitFor().fail()`

The `helper.waitFor()` function returns a jQuery Deferred object.
Deferred objects are supposed to have a `.fail()` method that is
chainable (it should return `this`). Before this change,
`helper.waitFor()` monkey-patched the `.fail()` method with a function
that returned `undefined`. Now the monkey-patched `.fail()` returns
the Deferred object.

Also modernize the code a bit.
---
 tests/frontend/helper.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tests/frontend/helper.js b/tests/frontend/helper.js
index e14169bb1..f36e45692 100644
--- a/tests/frontend/helper.js
+++ b/tests/frontend/helper.js
@@ -164,12 +164,12 @@ var helper = {};
 
     var deferred = $.Deferred();
 
-    var _fail = deferred.fail;
+    const _fail = deferred.fail.bind(deferred);
     var listenForFail = false;
-    deferred.fail = function(){
+    deferred.fail = (...args) => {
       listenForFail = true;
-      _fail.apply(this, arguments);
-    }
+      return _fail(...args);
+    };
 
     var intervalCheck = setInterval(function(){
       var passed = false;