Add file-loader to Karma so assets will resolve in tests

karma.conf.js

@@ -168,6 +168,10 @@ module.exports = function (config) {
                                   path.resolve('./test'),
                                  ]
                     },
+                    {
+                        test: /\.(gif|png|svg|ttf)$/,
+                        loader: 'file-loader',
+                    },
                 ],
                 noParse: [
                     // for cross platform compatibility use [\\\/] as the path separator

package.json

@@ -125,6 +125,7 @@
     "eslint-plugin-react": "^7.7.0",
     "estree-walker": "^0.5.0",
     "expect": "^23.6.0",
+    "file-loader": "^3.0.1",
     "flow-parser": "^0.57.3",
     "jest-mock": "^23.2.0",
     "karma": "^3.0.0",