Too Long; Didn't Read
When you start to write tests you could spread many duplicated rows of your code all over the tests. As an example for testing endpoints of the backend, I use the SuperTest(https://.com/visionmedia/supertest) It provides the ability to send HTTP requests to specific REST APIs. For the backend there can be some general things in the requests. For example Headers of the request. I guess you will require to include some common headers that are used everywhere in your API. Then it will be nice to have a common function for the tests to create a ‘request’ object.