Observer Never Fires

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName:'Ember Twiddle'
});

application.template.hbs

<h1>Welcome to {{appName}}</h1>

{{my-component testMe="Hello World"}}

<br>
<br>
{{outlet}}
<br>
<br>

my-component.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  testMe: null,
  testMeObserver: Ember.observer('testMe', function() {
  	console.log('This observer never fires.');
  })
});

my-component.template.hbs

{{yield}}

twiddle.json

{
  "version": "0.4.10",
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/1.13.9/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/1.13.11/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/1.13.9/ember-template-compiler.js"
  }
}