Re-add possibility to enable feature flags within Browser

Optional feature flags can now be enabled via a checkbox, rendered at
the top of the test page. The state of the checkbox is set as query
parameter in the URL.

An in-repo-addon ensures that the ENABLE_OPTIONAL_FEATURES flag works
correctly, when the tests are run inside a browser: the workaround using
the in-repo-addon is needed, since the flag needs to be set before
Ember.js is loaded, but there is currently no other way.

lib/enable-optional-features-via-url/index.js

@@ -0,0 +1,27 @@
+/*jshint node:true*/
+module.exports = {
+  name: 'enable-optional-features-via-url',
+
+  /**
+    So the ENABLE_OPTIONAL_FEATURES flag is considered correctly within the
+    index.html, it needs to be set before Ember.js is loaded. Since there is
+    currently no way to access the `window` object within config/environment.js
+    (and hereby check if there is a query parameter present for the checkbox),
+    a script is injected, before Ember.js is loaded. The script checks if there
+    is no value yet for the ENABLE_OPTIONAL_FEATURES flag, and if so, it sets
+    the flag to true when there is a `enableoptionalfeatures` query parameter.
+   */
+  contentFor: function(name) {
+    if (name === "vendor-prefix") {
+      var array = [
+        "<!-- injected by lib/enable-optional-features-via-url -->",
+        "window.EmberENV = window.EmberENV || {};",
+        "if (typeof window.EmberENV.ENABLE_OPTIONAL_FEATURES === 'undefined') {",
+        "  window.EmberENV.ENABLE_OPTIONAL_FEATURES = window.location.search.indexOf('enableoptionalfeatures') !== -1;",
+        "}"
+      ];
+
+      return array.join('\n');
+    }
+  }
+};

lib/enable-optional-features-via-url/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "enable-optional-features-via-url",
+  "keywords": [
+    "ember-addon"
+  ]
+}

package.json

@@ -66,6 +66,9 @@
     "ember-addon"
   ],
   "ember-addon": {
-    "configPath": "tests/dummy/config"
+    "configPath": "tests/dummy/config",
+    "paths": [
+      "lib/enable-optional-features-via-url"
+    ]
   }
 }

tests/test-helper.js

@@ -19,14 +19,8 @@ import Ember from 'ember';
 
 setResolver(resolver);
 
-const ENV = Ember.ENV;
-const QUNIT_PARAMS = QUnit.urlParams;
 const { assert } = QUnit;
 
-ENV.EXTEND_PROTOTYPES = QUNIT_PARAMS.extendprototypes;
-ENV.ENABLE_OPTIONAL_FEATURES = QUNIT_PARAMS.enableoptionalfeatures;
-ENV.ENABLE_DS_FILTER = true;
-
 QUnit.begin(function() {
   Ember.RSVP.configure('onerror', function(reason) {
     // only print error messages if they're exceptions;
@@ -76,6 +70,5 @@ assert.without = function(array, item)  {
 
 addEmberAssertions(assert);
 
-QUnit.config.testTimeout= 2000;
+QUnit.config.testTimeout = 2000;
 QUnit.config.urlConfig.push({ id: 'enableoptionalfeatures', label: "Enable Opt Features" });
-