Badger Academy Week 3

The third week of Badger Academy has passed, and with it ends the first cycle of seniors helping interns. For this thursday we were paired with Joe Stanton. We ran into a lot of problems during the week, which left us somewhat frustrated but also increased our eagerness to learn. Most of our environment setup for development has been done by this point. We managed to decrease our docker build times from ~20 minutes to 3-5 minutes depending on how good of a day the server was having, but overall it was consistent and fast.

Our focus this week was on testing standards. We were aware of the best practices for testing our software, but their implementations within our projects was what took the bulk of our time.

Testing the API

Testing the Rails backend was fairly straightforward. When we scaffolded the controllers and models for our project, a set of pre-generated RSpec tests was provided for us. Most of them were fairly unoptimised and some were not suited for an API, but rather a project written completely in Rails.

We kept a few things in mind while writing these tests;

  • Keep tests of one model/controller isolated from other models and controllers
  • Avoid hitting the database where we could.
  • Avoid testing things which are covered by higher level tests.

Expanding on that third point, Joe helped explain what layers to test and what layers we could skip. At the core of our app we have model tests, which would be independent of the database and would test things like logic and validation. These should eventually make up the majority of our tests, but for the meantime we only have a few validation checks. The 'medium-level' tests were things like routing and request tests.

We ended up skipping the routing tests since once we got to the higher-level integration tests, we could infer that if those passed then all our routing was correct. We kept request tests at a minimum, only checking that the API returned the correct status codes, so we could have a sense of consistency across our app, and those weren't necessarily implied by the integration tests.

Following that, we removed the unnecessary stuff and, through the use of FactoryGirl, we converted our logic and validation tests to avoid hitting the database, as it would cause a significant slowdown once our project became larger. Some of our higher level controller tests did hit the database, however this is unavoidable in most cases and attempting to bypass this would have been more trouble than it was worth.

Testing the Frontend

Our Frontend testing was much more difficult to set up. We're currently running a stack of PhantomJS, CucumberJS and Selenium. CucumberJS is a tool that allows us to write tests in a human-readable format, so that anyone, without an understanding of programming, could see what's happening and even write their own tests if they wanted to. This is the basic premise of BDD (behaviour-driven development) - we write tests for functionality of the software beforehand, from the standpoint of the end user and in a language that they can understand. This differentiates from the TDD (test-driven) principles used in the API as that is written purely in Ruby, and not necessarily from a user's point of view.

 

That's an example of a test written in Gherkin (the CucumberJS language - yes we are aware of all the slightly strange vegetable references). You can probably guess what it tests for. Behind the scenes, the software captures and identifies each of those lines and performs tests based on parameters that are specified (e.g. what page you're on and what action you're performing)

One issue we struggled past was how to go about isolating these tests from the API. Since the pages would have content from the backend displayed, we'd need a way to test using fake data. We went through a variety of methods during the week. Firstly, we thought of simply stubbing out the calls to the API using Sinon, a popular mocking and stubbing JavaScript library. While this would have been the most robust option, we had big difficulties using it with Browserify - a tool we are using which bundles your entire application into one file - and we decided on simply creating a fake api server using Stubby, which runs only for the duration of the tests and can serve multiple datasets to the frontend so we can still test a variety of cases.

CircleCI

Since we got the testing frameworks down, we expect to make fast progress from here on out. We ended up learning and using CircleCI, which will automatically run tests on any pushes or pull requests made to the github repos, and this makes sure we only merge stuff into master when everything is working as planned, and also makes sure that all tests are passing on a fresh system before deployment.

Despite all the new technology we have introduced, everything is going more or less smoothly and we couldn't ask for a better foundation to build this project from. Not only are we rethinking the way the tech badgers go about the development process, we also streamline the entire production process with lower build times, safe and consistent deployment and a highly scalable and portable infrastructure.