Mocking Stripe class constructor with jest.mock not working - node.js

Question

I am trying to mock Stripe's class constructor, but it does not seem to be working as it should according to Jest's docs. I followed these instructions in order to mock to the constructor.
Here is the controller code that uses Stripe (/src/controllers/stripe.ts):
import Stripe from 'stripe';
/**
* Creates a Stripe Customer
*
* #param {object} req The express request object.
* #param {object} res The express response object.
* #param {function} next The express next function.
*/
export const createStripeCustomer = async (
req: Request,
res: Response,
next: NextFunction
): Promise<Response | void> => {
const stripeApiKey: string = process.env.STRIPE_API_KEY ? process.env.STRIPE_API_KEY : '';
const user: IUser = req.user as IUser;
/** Send error if no Stripe API key or no user */
if (!stripeApiKey) {
return next(
'Something went wrong. If this problem persists, please contact technical support.'
);
} else if (!user) {
res.status(401);
return next('Unauthroized Access');
}
const stripe = new Stripe(stripeApiKey, {
apiVersion: '2020-03-02',
});
};
Here is the test code (/src/tests/controllers/stripe.ts):
import Stripe from 'stripe';
/**
* Return error if stripe.customer.create fails
*/
test('Should error if stripe.customer.create fails', async (done) => {
process.env.STRIPE_API_KEY = 'StripeAPIKey';
jest.mock('stripe', () => {
return jest.fn().mockImplementation(function () {
return {
customers: {
create: jest.fn().mockRejectedValue('Stripe error'),
},
};
});
});
mockRequest = ({
body: {
payment_method: mockPaymentMethodObject,
},
user: {
email: 'jdoe#google.com',
first_name: 'John',
last_name: 'Doe',
},
} as unknown) as Request;
await createStripeCustomer(mockRequest, mockResponse, mockNextFunction);
expect(mockNextFunction).toHaveBeenCalledTimes(1);
expect(mockNextFunction).toHaveBeenCalledWith('Stripe error');
done();
});
My expectation is that the test should pass, but I am getting the following error:
expect(jest.fn()).toHaveBeenCalledWith(...expected)
Expected: "Stripe error"
Received: [Error: Invalid API Key provided: StripeAPIKey]
Number of calls: 1
137 |
138 | expect(mockNextFunction).toHaveBeenCalledTimes(1);
> 139 | expect(mockNextFunction).toHaveBeenCalledWith('Stripe error');
| ^
140 | done();
141 | });
142 | test('Should error if user update fails', () => {});
at _callee3$ (src/tests/controllers/stripe.test.ts:139:30)
at tryCatch (node_modules/regenerator-runtime/runtime.js:45:40)
at Generator.invoke [as _invoke] (node_modules/regenerator-runtime/runtime.js:274:22)
at Generator.prototype.<computed> [as next] (node_modules/regenerator-runtime/runtime.js:97:21)
at asyncGeneratorStep (node_modules/#babel/runtime/helpers/asyncToGenerator.js:3:24)
at _next (node_modules/#babel/runtime/helpers/asyncToGenerator.js:25:9)
This seems to be throwing because Stripe is not being mocked and it is trying to authenticate with the API key of StripeAPIKey.
Update 1:
I also tried the following, which led to the same result:
import * as stripe from 'stripe';
jest.mock('stripe', () => {
return {
Stripe: jest.fn().mockImplementation(() => ({
customers: {
create: jest.fn().mockRejectedValueOnce('Stripe error'),
},
})),
};
});

Answer 1

I found this post and I'm not exactly sure why this worked instead of using jest.mock(), but here is how I got the tests to start passing. I created a separate file in /tests/__mocks__/.
/tests/mocks/stripe.js (Note: this is not a TS file)
export default class Stripe {}
and here is my new test in /tests/src/controllers/stripe.ts
/**
* Return error if stripe.customer.create fails
*/
test('Should error if stripe.customer.create fails', async (done) => {
Stripe.prototype.customers = ({
create: jest.fn().mockRejectedValueOnce('Stripe error'),
} as unknown) as Stripe.CustomersResource;
await createStripeCustomer(mockRequest, mockResponse, mockNextFunction);
expect(Stripe.prototype.customers.create).toHaveBeenCalledTimes(1);
expect(mockNextFunction).toHaveBeenCalledTimes(1);
expect(mockNextFunction).toHaveBeenCalledWith('Stripe error');
done();
});
If someone with more Jest/Typescript knowledge wants to shed some light on this. That would be great!