Jasmine-Node and Rewire, Part 2: Making the test complete

In the previous post I introduced the concept of using Rewire with Jasmine-Node to simplify Node.js unit testing. Rewire added a __set__ and a __get__ function to the module which let us grab a function in the module, and test it directly. We could test the function's output by controlling the objects that the function worked with, and checking them upon function completion. We didn't need to manipulate any internals of the function so our testing is still honoring the "Black Box" concept of unit testing. The idea is that the unit test only cares about what the testee can take in, return, and manipulate outside itself. How that operation is performed is not important to the unit test.

There was one test we didn't look at which I want to discuss now.

Jasmine-Node and Rewire, Part 1

Node.js development can be a lot of fun. Unit testing can be fun too. Unit testing Node can be very much not fun. Unit testing Nodejs modules often feels like trying to build a neutered integration test with mocks, nocks, and intercepts. Since Node is a web server whose functionality revolves around responding to http requests, the most natural testing method would be to trip those URLs and check the response. However, that ends up being more of a test of the middleware, and doesn't allow for testing the function directly. If you want to ignore the http calls, the most rational way to test the functions inside the module would be to export them. Once exported the tests can easily be run against the exported functions. The problem with exposing all the functions via export means functionality that should be private is no longer private.