Add public API for injection & registration

In an app, we encourages users to use injection over container.lookup,
and we encourage `application.register` over `registry.register`. But in
our integration tests, there is no good alternative to direct
`this.container.lookup` and `this.registry.register`.

So I added `register` and `inject` capability directly to the
integration test context. `register` is fairly trivial:

    test('registering something', function(assert) {
      this.register('component:x-foo', Ember.Component.extend({
        classNames: ['i-am-x-foo']
      }));
      this.render(hbs`{{x-foo}}`);
      assert.equal(this.$('.i-am-x-foo').length, 1, 'found x-foo');
    });

`inject` lets you inject anything into the test context:

    test('injecting a service', function(assert) {
      this.inject.service('notifications');
      this.render(hbs`{{my-notification-viewer}}`);

      // The notifications service has been injected into our test context,
      // so we can access it here and tell it to do something.
      this.get('notifications').receivedNotification("Hello world");

      assert.equal(this.$('.notification').text(), 'Hello world');
    })

You can also give the injected thing an alternate name using `as`:

    test('injecting a service with aliased name', function(assert) {
      this.inject.service('notifications', { as: 'messages' });
      this.render(hbs`{{my-notification-viewer}}`);

      // The notifications service has been injected into our test context
      // as this.get('messages').
      this.get('messages').receivedNotification("Hello world");

      assert.equal(this.$('.notification').text(), 'Hello world');
    })

lib/ember-test-helpers/test-module-for-component.js

@@ -188,6 +188,18 @@ export default TestModule.extend({
       }
       hook.apply(module, Array.prototype.slice.call(arguments, 1));
     };
+    context.register = function() {
+      var target = this.registry || this.container;
+      return target.register.apply(target, arguments);
+    };
+
+    context.inject = {};
+    Object.keys(Ember.inject).forEach(function(typeName) {
+      context.inject[typeName] = function(name, opts) {
+        var alias = (opts && opts.as) || name;
+        Ember.set(context, alias, module.container.lookup(typeName + ':' + name));
+      };
+    });
   },
 
   setupContext: function() {

tests/test-module-for-integration-test.js

@@ -191,6 +191,61 @@ moduleForComponent('Component Integration Tests: implicit views are not deprecat
 
 test('the toplevel view is not deprecated', function () {
   expect(0);
-  (this.registry || this.container).register('component:my-toplevel', this.container.lookupFactory('view:toplevel'));
+  this.register('component:my-toplevel', this.container.lookupFactory('view:toplevel'));
   this.render("{{my-toplevel}}");
 });
+
+
+moduleForComponent('Component Integration Tests: register and inject', {
+  integration: true
+});
+
+test('can register a component', function() {
+  this.register('component:x-foo', Ember.Component.extend({
+    classNames: ['i-am-x-foo']
+  }));
+  this.render("{{x-foo}}");
+  equal(this.$('.i-am-x-foo').length, 1, "found i-am-x-foo");
+});
+
+test('can register a service', function() {
+  this.register('component:x-foo', Ember.Component.extend({
+    unicorn: Ember.inject.service(),
+    layout: Ember.Handlebars.compile('<span class="x-foo">{{unicorn.sparkliness}}</span>')
+  }));
+  this.register('service:unicorn', Ember.Component.extend({
+    sparkliness: 'extreme'
+  }));
+  this.render("{{x-foo}}");
+  equal(this.$('.x-foo').text().trim(), "extreme");
+});
+
+test('can inject a service directly into test context', function() {
+  this.register('component:x-foo', Ember.Component.extend({
+    unicorn: Ember.inject.service(),
+    layout: Ember.Handlebars.compile('<span class="x-foo">{{unicorn.sparkliness}}</span>')
+  }));
+  this.register('service:unicorn', Ember.Component.extend({
+    sparkliness: 'extreme'
+  }));
+  this.inject.service('unicorn');
+  this.render("{{x-foo}}");
+  equal(this.$('.x-foo').text().trim(), "extreme");
+  this.set('unicorn.sparkliness', 'amazing');
+  equal(this.$('.x-foo').text().trim(), "amazing");
+});
+
+test('can inject a service directly into test context, with aliased name', function() {
+  this.register('component:x-foo', Ember.Component.extend({
+    unicorn: Ember.inject.service(),
+    layout: Ember.Handlebars.compile('<span class="x-foo">{{unicorn.sparkliness}}</span>')
+  }));
+  this.register('service:unicorn', Ember.Component.extend({
+    sparkliness: 'extreme'
+  }));
+  this.inject.service('unicorn', { as: 'hornedBeast' });
+  this.render("{{x-foo}}");
+  equal(this.$('.x-foo').text().trim(), "extreme");
+  this.set('hornedBeast.sparkliness', 'amazing');
+  equal(this.$('.x-foo').text().trim(), "amazing");
+});