Make sure the same sandbox class and sandbox globals are used during reloads

When reloading the app (for exampel during rebuilds), we need to make sure we use the same sandbox class and the same set of sandboxGlobals that were used to initial creation of AppInstance.

Discovered this while working on the serve refactor in ember-cli-fastboot.

Author: kratiahuja

src/ember-app.js

@@ -60,7 +60,6 @@ class EmberApp {
    * @param {Object} [sandboxGlobals={}] any additional variables to expose in the sandbox or override existing in the sandbox
    */
   buildSandbox(distPath, sandboxClass, sandboxGlobals) {
-    let Sandbox = sandboxClass || require('./vm-sandbox');
     let sandboxRequire = this.buildWhitelistedRequire(this.moduleWhitelist, distPath);
     let config = this.appConfig;
     function appConfig() {
@@ -81,7 +80,7 @@ class EmberApp {
       }
     }
 
-    return new Sandbox({
+    return new sandboxClass({
       globals: globals
     });
   }

src/index.js

@@ -45,7 +45,7 @@ class FastBoot {
     options = options || {};
 
     this.distPath = options.distPath;
-    this.sandbox = options.sandbox;
+    this.sandbox = options.sandbox || require('./vm-sandbox');
     this.sandboxGlobals = options.sandboxGlobals || {};
     this.resilient = !!options.resilient || false;
 
@@ -91,11 +91,14 @@ class FastBoot {
       this._app.destroy();
     }
 
-    this._buildEmberApp(options ? options.distPath : null);
+    options = options || {};
+    this._buildEmberApp(options.distPath || null);
   }
 
   _buildEmberApp(distPath, sandbox, sandboxGlobals) {
     distPath = distPath || this.distPath;
+    sandbox = sandbox || this.sandbox;
+    sandboxGlobals = sandboxGlobals || this.sandboxGlobals;
 
     if (!distPath) {
       throw new Error('You must instantiate FastBoot with a distPath ' +

test/fastboot-test.js

@@ -202,6 +202,62 @@ describe("FastBoot", function() {
     }
   });
 
+  it("can reload the app using the same sandboxGlobals", function() {
+    var fastboot = new FastBoot({
+      distPath: fixture('basic-app'),
+      sandboxGlobals: {
+        foo: 5,
+        najax: 'undefined',
+        myVar: 'undefined'
+      }
+    });
+
+    return fastboot.visit('/')
+      .then(r => r.html())
+      .then(html => expect(html).to.match(/Welcome to Ember/))
+      .then(hotReloadApp)
+      .then(() => fastboot.visit('/foo'))
+      .then(r => r.html())
+      .then((html) => {
+        expect(html).to.match(/foo from sandbox: 5/);
+        expect(html).to.match(/najax in sandbox: undefined/);
+      });
+
+    function hotReloadApp() {
+      fastboot.reload({
+        distPath: fixture('custom-sandbox')
+      });
+    }
+  });
+
+  it("can reload the app using the same sandbox class", function() {
+    var fastboot = new FastBoot({
+      distPath: fixture('basic-app'),
+      sandbox: CustomSandbox,
+      sandboxGlobals: {
+        myVar: 2,
+        foo: 'undefined',
+        najax: 'undefined'
+      }
+    });
+
+    return fastboot.visit('/')
+      .then(r => r.html())
+      .then(html => expect(html).to.match(/Welcome to Ember/))
+      .then(hotReloadApp)
+      .then(() => fastboot.visit('/foo'))
+      .then(r => r.html())
+      .then((html) => {
+        expect(html).to.match(/myVar in sandbox: 2/);
+      });
+
+    function hotReloadApp() {
+      fastboot.reload({
+        distPath: fixture('custom-sandbox')
+      });
+    }
+  });
+
   it("reads the config from package.json", function() {
     var fastboot = new FastBoot({
       distPath: fixture('config-app')