add basic test, disable etag on post routes as well, paypal ipn: prevent set headers after response error

test/api/unit/middlewares/cache.test.js

@@ -0,0 +1,31 @@
+import {
+  generateRes,
+  generateReq,
+  generateNext,
+} from '../../../helpers/api-unit.helper';
+import {
+  disableCache,
+} from '../../../../website/server/middlewares/cache';
+
+describe('cache middlewares', () => {
+  let res; let req; let
+    next;
+
+  beforeEach(() => {
+    req = generateReq();
+    res = generateRes();
+    next = generateNext();
+  });
+
+  describe('disableCache', () => {
+    it('sets the correct headers', () => {
+      disableCache(req, res, next);
+      expect(res.set).to.have.been.calledWith('Cache-Control', 'no-store');
+      expect(next).to.have.been.calledOnce;
+    });
+
+    xit('removes the etag header', () => {
+      // @TODO how to stub onHeaders
+    });
+  });
+});