[update] improve test to stop using deprecated syntax
[update] improve test to stop using deprecated syntax

fastly/ember-stripe-service,ride/ember-stripe-service,fastly/ember-stripe-service,sescobb27/ember-stripe-service,iezer/ember-stripe-service,samselikoff/ember-stripe-service,samselikoff/ember-stripe-service,sescobb27/ember-stripe-service,iezer/ember-stripe-service,ride/ember-stripe-service