How can I unit test a method that results in an Action

In my Ember application, I have a simple form component, with the following behavior (snippet):

...
let searchText = this.get('searchText') &&
  this.get('searchText').trim().toLowerCase();

this.sendAction('searchTextChanged', searchText);
...

How can I unit test this functionality in a qunit test? I'm unable to figure out how to listen for the action result. I'm using the test functionality that comes with ember-cli -- qunit, the helpers, etc.