Paypal refactor lib (#8420)

* Abstracted paypal logic from controller. Added intial tests

* Added checkout tests

* Added checkout success test

* Added subscribe test

* Added subscribeSuccess tests

* Added subscribeCancel tests

* Added ipn tests

* Fixed broken test

* Added integration tests and fixed linting issues

* Added errors for paypal checkout success integration test

* Removed extra test

* Removed pending status from subscribe cancel test

* Added more error checking and tests

* Fixed lint issues

test/api/v3/integration/payments/paypal/POST-payments_paypal_ipn.test.js

@@ -0,0 +1,44 @@
+import {
+  generateUser,
+} from '../../../../../helpers/api-integration/v3';
+import paypalPayments from '../../../../../../website/server/libs/paypalPayments';
+
+describe('payments - paypal - #ipn', () => {
+  let endpoint = '/paypal/ipn';
+  let user;
+
+  beforeEach(async () => {
+    user = await generateUser();
+  });
+
+  it('verifies credentials', async () => {
+    let result = await user.post(endpoint);
+    expect(result).to.eql('OK');
+  });
+
+  describe('success', () => {
+    let ipnStub;
+
+    beforeEach(async () => {
+      ipnStub = sinon.stub(paypalPayments, 'ipn').returnsPromise().resolves({});
+    });
+
+    afterEach(() => {
+      paypalPayments.ipn.restore();
+    });
+
+    it('makes a purchase', async () => {
+      user = await generateUser({
+        'profile.name': 'sender',
+        'purchased.plan.customerId': 'customer-id',
+        'purchased.plan.planId': 'basic_3mo',
+        'purchased.plan.lastBillingDate': new Date(),
+        balance: 2,
+      });
+
+      await user.post(endpoint);
+
+      expect(ipnStub).to.be.calledOnce;
+    });
+  });
+});