Use Application.create().buildInstance() when possible.

addon-test-support/application.js

@@ -0,0 +1,9 @@
+var __application__;
+
+export function setApplication(Application) {
+  __application__ = Application.create({ autoboot: false });
+}
+
+export function getApplication() {
+  return __application__;
+}

addon-test-support/build-owner.js

@@ -4,21 +4,14 @@ import global from './global';
 import ApplicationInstance from '@ember/application/instance';
 import Application from '@ember/application';
 import EmberObject from '@ember/object';
+import { Promise } from 'rsvp';
 
 import require from 'require';
 import Ember from 'ember';
 import { getResolver } from './resolver';
+import { getApplication } from './application';
 
-const Owner = (function() {
-  // this module only supports Ember 2.4+ but is evaluated
-  // on older Ember versions (which we support via the legacy-0-6 API)
-  // and calling `.extend` with undefined is an issue
-  if (Ember._RegistryProxyMixin && Ember._ContainerProxyMixin) {
-    return EmberObject.extend(Ember._RegistryProxyMixin, Ember._ContainerProxyMixin);
-  }
-
-  return EmberObject.extend();
-})();
+let Owner;
 
 // different than the legacy-0-6-x version (build-registry.js)
 // in the following ways:
@@ -27,6 +20,15 @@ const Owner = (function() {
 // * returns "owner" (instead of a POJO with registry/container)
 // * directly calls getResolver if one was not provided
 export default function(resolver = getResolver()) {
+  let application = getApplication();
+  if (application) {
+    return application.boot().then(app => app.buildInstance().boot());
+  }
+
+  if (Owner === undefined) {
+    Owner = EmberObject.extend(Ember._RegistryProxyMixin, Ember._ContainerProxyMixin);
+  }
+
   let fallbackRegistry, registry, container;
   let namespace = EmberObject.create({
     Resolver: {
@@ -104,5 +106,5 @@ export default function(resolver = getResolver()) {
     }
   }
 
-  return owner;
+  return Promise.resolve().then(() => owner);
 }

addon-test-support/index.js

@@ -5,6 +5,7 @@ export { default as TestModuleForComponent } from './legacy-0-6-x/test-module-fo
 export { default as TestModuleForModel } from './legacy-0-6-x/test-module-for-model';
 
 export { setResolver } from './resolver';
+export { setApplication } from './application';
 export {
   default as setupContext,
   getContext,

addon-test-support/setup-context.js

@@ -61,10 +61,13 @@ export default function(context, options = {}) {
 
   return new Promise(resolve => {
     // ensure "real" async and not "fake" RSVP based async
-    next(() => {
+    next(resolve);
+  })
+    .then(() => {
       let resolver = options.resolver;
-      let owner = buildOwner(resolver);
-
+      return buildOwner(resolver);
+    })
+    .then(owner => {
       context.owner = owner;
 
       context.set = function(key, value) {
@@ -110,7 +113,6 @@ export default function(context, options = {}) {
       _setupAJAXHooks();
       _setupPromiseListeners();
 
-      resolve(context);
+      return context;
     });
-  });
 }

tests/helpers/resolver.js

@@ -3,8 +3,9 @@ import { run } from '@ember/runloop';
 import { dasherize } from '@ember/string';
 import AppResolver from '../../resolver';
 import config from '../../config/environment';
-import { setResolver } from 'ember-test-helpers';
+import { setResolver, setApplication } from 'ember-test-helpers';
 import require from 'require';
+import App from '../../app';
 
 const Resolver = AppResolver.extend({
   registry: {},
@@ -22,6 +23,7 @@ resolver.namespace = {
 };
 
 setResolver(resolver);
+setApplication(App);
 
 export function setResolverRegistry(registry) {
   run(resolver, 'set', 'registry', registry);