Capybara VS Simple Form

Cuba takes help from a lot of other technologies to bring the best of everything. For example, the responses in Cuba are the optimized version of the Rack responses. The templates are integrated via Tilt and testing via Cutest and Capybara.

I am going to use a browser based testing tool called Playwright (But you could use Capybara, or Selenium WebDriver etc.).

Even as a much smaller team, building Heii On-Call [0] as a lightweight alerting/monitoring/on-call rotations SaaS based on Ruby on Rails has basically been a pleasure!

And as the article highlights, perhaps the key reason for smooth deployments and upgrades is that the CI testing story is so, so good: RSpec [1] plus Capybara [2] for us. That means we have decently extensive tests of just about all behavior. The few small Rails and Ruby upgrades we've done have gone quite smoothly and confidently, with usually just a few non-Rails gem dependencies needing to be manually updated as well.

The "microservices" story is where we've pulled in the Crystal programming language [3] to great effect. After dabbling with Go and Rust, we've found that Crystal is truly a breath of fresh air. Crystal powers the parts of Heii On-Call that need to be fast and low-RAM, specifically the inbound API https://api.heiioncall.com/ and the outbound HTTP(S) prober background processes. I've ported some shared utility classes from Ruby to Crystal almost completely by just copy-and-pasting ___.rb to ___.cr; porting the tests for those classes was far more onerous than porting the class code itself. (Perhaps another point of evidence toward the superiority of RoR's testing story...)

The front-end story is nice but just a bit weaker. Using Hotwire / Turbo successfully, but I have an open PR to fix a fairly obvious stale cache bug in Turbo [4] that has been sitting unloved for nearly a month, despite other users reporting the same issue. I'm hopeful that it will get merged in the next release, but definitely less active than the backend side.

For me, the key conclusion is that the excellent Ruby on Rails testing story is what enables everything to go a lot more smoothly and have such a strong foundation. I'd be curious if any GitHubbers can talk more about whether they too are using Rspec+Capybara or something else? Are there internal guidelines for test coverage?

[0] https://heiioncall.com/

[1] https://rspec.info/

[2] https://github.com/teamcapybara/capybara

[3] https://crystal-lang.org/

[4] https://github.com/hotwired/turbo/pull/895

Engineering at Aha! focuses on using and improving the Capybara test framework. We have added many helpers and additional functionality to make working with Capybara easy. Testing at mobile widths is another chance to improve our testing tooling. Here is the incremental approach that we used to add mobile testing helpers.

Since the Capybara library drives the underlying tests, Minitest also has the same syntax.

We can write component tests with any language or framework, but the most popular ones are probably Cucumber and Capybara.

The nice thing about partial templates is that templates are unit-testable with View specs (or similarly in Minitest) and the rendered output can even be verified using Capybara matchers.

To piggyback: This would be a type of browser test, so you would want to use something like Cypress (https://github.com/testdouble/cypress-rails) or Capybara (https://github.com/teamcapybara/capybara). RSpec has a good integration with Capybara. Cypress is JS-based so it will require some additional config.

When you write a system test (or, as we prefer, a system spec) with Ruby on Rails, you're exercising the whole stack from the point of view of the user. So, naturally, you have to do things like make sure that certain elements are on the page and work as you expect when you click on then, type in them, and drag them around. Capybara works exceedingly well for this, giving you a lovely API for querying HTML.

I also tend to use gems like simple_form to generate my form HTML, and this saves me from having to maintain a lot of view code to outputting translated content onto forms. Also simple_form has it's own i18n convention that compliments the Rails default pretty well.

I followed the RailsCasts tutorial and its GitHub page to set up the gem in my application and used it for all of the models in my application. It was working perfectly fine showing the default error message at the top and the validation message at the bottom of their respective fields.

Okay now for those "buttons". We don't want just a normal button or link though. This is where we need the booking update form. Let's use simple_form_for (check out the docs here).

There are many ways to create a form in Rails, whether you want to create a form with Form builder from Rails itself or maybe using third party gem like simple_form. Of course, simple_form is not the only option we have to build form in rails, there are alternatives out there such as formtastic, cocoon, nested_form, etc. However, in this post I'm going to give you a basic use case to use simple_form in Rails application.

I usually go with simple_form, I customise my forms by configuring it and letting it handle the repeated rendering.

Simple Form gem

The biggest unclear area that we saw related to view components were forms. There were glimpses of compatibility issues with Rails form helpers in the documentation and we saw a recent effort of the team to mitigate them. Moreover, we were used to building forms with Simple Form which added another variable to the equation. And, in general, we considered the Rails form builders (as well as the Simple Form builder) a system of form-related components in the first place so we were unsure how this would fit into the View Components ecosystem or whether we should even try to do that.

Learn more about simple form: 1) https://github.com/heartcombo/simple_form 2) https://www.youtube.com/watch?v=NfZk74R2Oi4&t=5s