slider is undefined in integration test, leading to failure with "Cannot read property 'on'/'off' of undefined"

[arnebit]

I just added this component to an ember 3.12 app and now the integration test for the component using the range-slider fails:

1. TypeError: Cannot read property 'on' of undefined
   at range-slider.js:75
   at Array.forEach ()
   at Class.setup (range-slider.js:71)
   at Class.didInsertElement (range-slider.js:50)
   at Class.trigger (core_view.js:69)
   at Class.superWrapper [as trigger] (utils.js:365)
   at CurlyComponentManager.didCreate (glimmer.js:5664)
   at Transaction.commit (runtime.js:3203)
   at Environment$1.commit (runtime.js:3298)
   at Environment$1.commit (glimmer.js:4712)

2. (the actually present assertion in the near-dummy test passes)

3. TypeError: Cannot read property 'off' of undefined
   at Class.teardown (http://localhost:4200/assets/vendor.js:280722:14)
   at Class.willDestroyElement (http://localhost:4200/assets/vendor.js:280717:12)
   at Class.trigger (http://localhost:4200/assets/vendor.js:60822:23)
   at Class.superWrapper [as trigger] (http://localhost:4200/assets/vendor.js:58181:22)
   at ComponentStateBucket.destroy (http://localhost:4200/assets/vendor.js:33130:19)
   [...]