fix[babel options] don't overwrite existing babel options (#19)

index.js

@@ -34,13 +34,17 @@ module.exports = {
         ]
       };
 
-      this.options.babel = {
-        plugins: [
-          [FilterImports, strippedImports],
-          [RemoveImports, 'ember-attacher/-debug/helpers']
-        ],
-        postTransformPlugins: [StripClassCallCheck]
-      };
+      // In some versions of Ember, this.options is undefined during tests
+      this.options = this.options || {};
+
+      // Make sure the babel options are accessible
+      let babelOptions = this.options.babel = this.options.babel || {};
+      babelOptions.plugins = babelOptions.plugins || [];
+      babelOptions.postTransformPlugins = babelOptions.postTransformPlugins || [];
+
+      babelOptions.plugins.push([FilterImports, strippedImports]);
+      babelOptions.plugins.push([RemoveImports, 'ember-attacher/-debug/helpers']);
+      babelOptions.postTransformPlugins.push(StripClassCallCheck);
     }
 
     this._hasSetupBabelOptions = true;

package.json

@@ -28,7 +28,7 @@
     "ember-cli-babel": "^6.3.0",
     "ember-cli-htmlbars": "^1.3.3",
     "ember-cli-sass": "^7.0.0",
-    "ember-popper": "^0.3.1",
+    "ember-popper": "^0.3.2",
     "ember-truth-helpers": "^1.3.0"
   },
   "devDependencies": {

yarn.lock

@@ -2487,9 +2487,9 @@ ember-native-dom-helpers@^0.5.0:
     broccoli-funnel "^1.1.0"
     ember-cli-babel "^6.1.0"
 
-ember-popper@^0.3.1:
-  version "0.3.1"
-  resolved "https://registry.yarnpkg.com/ember-popper/-/ember-popper-0.3.1.tgz#9593d9e5ccddc909f4d7be3359c596edcc88f0d1"
+ember-popper@^0.3.2:
+  version "0.3.2"
+  resolved "https://registry.yarnpkg.com/ember-popper/-/ember-popper-0.3.2.tgz#4adcd33fc1a3126eb2e07a76021b12c31ca40c31"
   dependencies:
     babel-plugin-filter-imports "^0.3.1"
     babel6-plugin-strip-class-callcheck "^6.0.0"