Unit Tests in Serverless / Jest encountered an unexpected token

Hey! Got the error:
notes-app-api@1.1.0 test /home/tuncar/Desktop/AWS/notes-app-api


FAIL tests/billing.test.js
● Test suite failed to run

Jest encountered an unexpected token

This usually means that you are trying to import a file which Jest cannot parse, e.g. it's not plain JavaScript.

By default, if Jest sees a Babel config, it will use that to transform your files, ignoring "node_modules".

Here's what you can do:
 • To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
 • If you need a custom transformation specify a "transform" option in your config.
 • If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.

You'll find more details and examples of these config options in the docs:


({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import { calculateCost } from "../libs/billing-lib";

SyntaxError: Unexpected token {

  at ScriptTransformer._transformAndBuildScript (node_modules/@jest/transform/build/ScriptTransformer.js:537:17)
  at ScriptTransformer.transform (node_modules/@jest/transform/build/ScriptTransformer.js:579:25)

Test Suites: 1 failed, 1 total
Tests: 0 total
Snapshots: 0 total
Time: 3.267s
Ran all test suites.
npm ERR! Test failed. See above for more details.

Help me please

If you are using the starter project that comes with the guide, you should use this instead to run your tests (in your package.json):

"scripts": {
  "test": "serverless-bundle test"

And run it using npm run test.