It happens that server does not return the data you requested for and throws a generic error. In these situations you want to show a friendly message to the user or handling the error by redirecting to another page. In this example I’m using Ember CLI Mirage and configured it to return a 403 response when requesting /posts.
Then in the modelhook where the endpoint is being called, I would need to looks for any error that may occur and handle them accordingly.
Side note: destructuring adapter errors from DS makes the code more readable.
And here is an acceptance test to cover this scenario.