chore: use identity-obj-proxy for jest css styles

Author: adamweeks

__mocks__/style-mock.js

@@ -6,7 +6,7 @@
   "testPathIgnorePatterns": ["<rootDir>/node_modules/"],
   "transformIgnorePatterns": ["<rootDir>/node_modules/"],
   "moduleNameMapper": {
-    "^.+\\.(css|less)$": "<rootDir>/__mocks__/style-mock.js",
+    "^.+\\.(css|less)$": "identity-obj-proxy",
     "^.+\\.(mp3|wav)$": "<rootDir>/__mocks__/sound-mock.js",
     "^.+\\.(gif|ttf|eot|svg|png|jpg)$": "<rootDir>/__mocks__/file-mock.js",
     "@ciscospark/(.*)": "<rootDir>/packages/node_modules/@ciscospark/$1/src"

jest.config.json

@@ -121,6 +121,7 @@
     "extract-text-webpack-plugin": "^2.0.0",
     "file-loader": "^0.11.1",
     "html-webpack-plugin": "^2.24.1",
+    "identity-obj-proxy": "^3.0.0",
     "inline-environment-variables-webpack-plugin": "^1.1.0",
     "jest": "^20.0.4",
     "json-loader": "^0.5.4",