I have an express app with a CRUD API (with sequelize) and I want to test it with Jest. I'm pretty new in unit-testing so I follow this guide, recommended by Jest's website.
The problem I have is that my app is built with ES6 modules and Jest ES6 modules is experimental and it seems that it doesn't "import" packages.
I have this test (took from the guide)
import request from 'supertest';
import app from '../app';
describe('Test the root path', () => {
test('It should response the GET method', done => {
request(app)
.get('/')
.then(response => {
expect(response.statusCode).toBe(404);
done();
});
});
});
And when I launched it (with NODE_OPTIONS=--experimental-vm-modules npx jest
I had to follow this jest wiki page), It says that
'sequelize' does not provide an export named 'DataTypes'
and when I launch my app normally (like with npm start
) it works fine, without any problems.
(the complete error log):
(node:49576) ExperimentalWarning: VM Modules is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
FAIL __tests__/app_test.js
● Test suite failed to run
SyntaxError: The requested module 'sequelize' does not provide an export named 'DataTypes'
at Runtime.linkAndEvaluateModule (node_modules/jest-runtime/build/index.js:779:5)
at TestScheduler.scheduleTests (node_modules/@jest/core/build/TestScheduler.js:333:13)
at runJest (node_modules/@jest/core/build/runJest.js:404:19)
at _run10000 (node_modules/@jest/core/build/cli/index.js:320:7)
at runCLI (node_modules/@jest/core/build/cli/index.js:173:3)
(and my Jest config)
// Sync object
/** @type {import('@jest/types').Config.InitialOptions} */
export default async () => {
return {
verbose: true,
transform: {},
};
};
Am I doing something wrong ? Should I change to commonJS instead of ES6
Thank you.
This is a known problem in Jest: #9771. It is said to be fixed in [email protected]
.
An interesting hack to work around this problem is to remove the main
field from the package.json
of the imported project.