Testing the multi-subdomain Rails app

Writing tests for a multi-tenant , multi-subdomain app turns out to be very tricky to figure out, e.g.:

I saw that, and understood the frustration. Integration tests (“ request specs ” or “ feature specs “) are built on a stack of frequently changing libraries and shifting API’s. And the recipe for subdomain-aware testing isn’t documented in any particular tool’s notes. So here’s my working configuration for Rails 5.2.0, in mid-2018.

The goal: feature- and request-specs to specific hostnames

I’m creating a set of sites with laws for each state:

texas.public.law , newyork.public.law , etc.

And there’s one “organizational home site”:

www.public.law

…with pages like About and Contact Us. I want to write request specs like these:

...and feature specs like this:

Spec helpers: get_path and visit_path

I’ve written two helpers, seen in the examples above: get_path for request specs, and visit_path for feature specs. get_path turned out to need very little code. However, it was difficult to figure out because it required reaching through RSpec, the Rails “integration” test support (to get the headers: parameter) and Rails APIs to determine that host: is the correct header to supply:

The equivalent code for feature specs, which are based on Capybara, requires a bit more work:

I simply place these helpers in my rails_helper.rb file.