Here's a StackBlitz with the directive working for reference.
@prestonjlamb I think the `mockElementRef` needs more of the API mocked. Take a look at the `fromEvent` source: https://github.com/ReactiveX/rxjs/blob/7.8.0/src/internal/observable/fromEvent.ts#L233
It's checking the target that you pass in for event listener and emitter methods. If it can't find them, it errors out with `Invalid event target`.