V3 payments 6 (#7104)

* payments api: cancelSubscription

* some more tests for amazon payments

* promisifying amazon payments

* somehow payment stub is not working

* cleaning up tests

* renaming tests in api/v3/integration/payments

* improvements

* cleanup, lint

* fixes as per comments

* moment.zone() is back in.

test/api/v3/integration/payments/POST-payments_amazon_createOrderReferenceId.test.js

@@ -0,0 +1,22 @@
+import {
+  generateUser,
+} from '../../../../helpers/api-integration/v3';
+
+describe('payments - amazon - #createOrderReferenceId', () => {
+  let endpoint = '/payments/amazon/createOrderReferenceId';
+  let user;
+
+  beforeEach(async () => {
+    user = await generateUser();
+  });
+
+  it('verifies billingAgreementId', async (done) => {
+    try {
+      await user.post(endpoint);
+    } catch (e) {
+      // Parameter AWSAccessKeyId cannot be empty.
+      expect(e.error).to.eql('BadRequest');
+      done();
+    }
+  });
+});