npm install stripe
pip install stripe

import Stripe from 'stripe';
const stripe = new Stripe(process.env.STRIPE_TEST_KEY!);

test('successful payment via 4242', async () => {
  const intent = await stripe.paymentIntents.create({
    amount: 1000,
    currency: 'usd',
    payment_method: 'pm_card_visa',
    confirm: true,
    return_url: 'https://example.com/return',
  });
  expect(intent.status).toBe('succeeded');
});

test('declined payment', async () => {
  await expect(
    stripe.paymentIntents.create({
      amount: 1000,
      currency: 'usd',
      payment_method: 'pm_card_chargeDeclined',
      confirm: true,
      return_url: 'https://example.com/return',
    })
  ).rejects.toThrow(/card was declined/);
});

import { buffer } from 'micro';
import handler from './stripe-webhook';

test('webhook handler validates signature', async () => {
  const payload = JSON.stringify({ type: 'payment_intent.succeeded', data: {...} });
  const signature = stripe.webhooks.generateTestHeaderString({
    payload,
    secret: process.env.STRIPE_WEBHOOK_SECRET!,
  });

  const req = { headers: { 'stripe-signature': signature }, body: Buffer.from(payload) };
  const res = await handler(req as any);
  expect(res.statusCode).toBe(200);
});

stripe listen --forward-to http://localhost:3000/webhooks/stripe
# Forwards real Stripe webhook events to your local endpoint

stripe trigger payment_intent.succeeded
# Sends a synthetic event to test your handler

test('idempotency key prevents duplicate charges', async () => {
  const key = 'order-12345';
  const r1 = await stripe.paymentIntents.create({...}, { idempotencyKey: key });
  const r2 = await stripe.paymentIntents.create({...}, { idempotencyKey: key });
  expect(r1.id).toBe(r2.id);  // Same PaymentIntent
});

npm test

stripe listen --forward-to http://localhost:3000/webhooks/stripe &
npm test

jobs:
  stripe-tests:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v5
      - uses: actions/setup-node@v4
      - run: npm ci && npm test
        env:
          STRIPE_TEST_KEY: ${{ secrets.STRIPE_TEST_KEY }}
          STRIPE_WEBHOOK_SECRET: ${{ secrets.STRIPE_WEBHOOK_SECRET }}