self.addEventListener('paymentrequest', event => {
  const expectedId = 'test-payment-request-identifier';
  if (event.paymentRequestId !== expectedId) {
    const msg = `Expected payment request identifier "${expectedId}", but got "${
      event.paymentRequestId
    }"`;
    event.respondWith(Promise.reject(new Error(msg)));
    return;
  }

  if (event.methodData.length !== 1) {
    const msg = `Expected one method data, but got ${
      event.methodData.length
    } instead`;
    event.respondWith(Promise.reject(new Error(msg)));
    return;
  }

  const methodData = event.methodData[0];
  const expectedMethodName = 'basic-card';
  if (methodData.supportedMethods !== expectedMethodName) {
    const msg = `Expected payment method name "${expectedMethodName}", but got "${
      methodData.supportedMethods
    }"`;
    event.respondWith(Promise.reject(new Error(msg)));
    return;
  }

  if (methodData.data.supportedNetworks) {
    const msg =
      'Expected no supported networks in payment method specific data';
    event.respondWith(Promise.reject(new Error(msg)));
    return;
  }

  const supportedTypes = methodData.data.supportedTypes;
  if (!supportedTypes) {
    const msg = 'Expected supported types in payment method specific data';
    event.respondWith(Promise.reject(new Error(msg)));
    return;
  }

  if (supportedTypes.length !== 1) {
    const msg = `Expected one supported type, but got ${
      supportedTypes.length
    } instead`;
    event.respondWith(Promise.reject(new Error(msg)));
    return;
  }

  const supportedType = supportedTypes[0];
  const expectedSupportedType = 'prepaid';
  if (supportedType !== expectedSupportedType) {
    const msg = `Expected supported type "${expectedSupportedType}", but got "${supportedType}"`;
    event.respondWith(Promise.reject(new Error(msg)));
    return;
  }

  if (methodData.displayItems) {
    const msg = 'Expected no display items';
    event.respondWith(Promise.reject(new Error(msg)));
    return;
  }

  const total = event.total;
  if (!total) {
    const msg = 'Expected total';
    event.respondWith(Promise.reject(new Error(msg)));
    return;
  }

  if (total.label) {
    const msg = 'Expected no total label';
    event.respondWith(Promise.reject(new Error(msg)));
    return;
  }

  const expectedCurrency = 'USD';
  if (total.currency !== expectedCurrency) {
    const msg = `Expected currency "${expectedCurrency}", but got "${
      total.currency
    }"`;
    event.respondWith(Promise.reject(new Error(msg)));
    return;
  }

  const expectedValue = '0.01';
  if (total.value !== expectedValue) {
    const msg = `Expected value "${expectedValue}", but got "${total.value}"`;
    event.respondWith(Promise.reject(new Error(msg)));
    return;
  }

  event.respondWith({
    methodName: 'basic-card',
    details: {
      billingAddress: {
        addressLine: ['1875 Explorer St #1000'],
        city: 'Reston',
        country: 'US',
        dependentLocality: '',
        languageCode: '',
        organization: 'Google',
        phone: '+15555555555',
        postalCode: '20190',
        recipient: 'Jon Doe',
        region: 'VA',
        sortingCode: '',
      },
      cardNumber: '4111111111111111',
      cardSecurityCode: '123',
      cardholderName: 'Jon Doe',
      expiryMonth: '12',
      expiryYear: '2028',
    },
  });
});