[coorasse]

When a failing expectation involves a Capybara element (e.g. expect(page.find("button")).to be_disabled), SuperDiff builds the failure message by walking the element's instance variables.

An element holds the session, and through it the driver and the browser connection (pages, network traffic, sockets). With CDP-based drivers like Cuprite/Ferrum this takes minutes, so the spec looks like it's hanging.

This adds an inspection tree builder for Capybara::Node::Base and Capybara::Driver::Node that uses Capybara's own #inspect (e.g. #<Capybara::Node::Element tag="h1" path="/html/body/h1">), mirroring the existing ActionDispatch::Request builder. It's loaded by super_diff/rspec when Capybara is present, or explicitly via require "super_diff/capybara".

Capybara is added to the Rails appraisals so the unit specs can run against a real rack_test session.

[jas14]

Hey @coorasse , thanks for the PR.

There are two parts of SuperDiff's output. The first is the inspection, which affects how the "expected ... to eq/match/whatever ..." output looks. It looks like you've got that covered here; reusing Capybara's own #inspect seems reasonable to me.

The other part, which doesn't seem to be covered by this PR yet, is the diff, which comes below the inspection. See this output screenshot.

I'm not familiar with Capybara, so I can't weigh in with much technical detail about how it should look. But if you don't add an operation tree builder, SuperDiff will select the default operation tree builder, which inspects instance variables, which will presumably do the thing we're trying to avoid here = walk into the driver.

[coorasse]

Thank you Joe for the feedback! I hopefully applied the changes you requested.
I've added a differ for Capybara nodes, so it looks something like this:

- #<Capybara::Node::Element tag="h1" path="/html/body/h1">
+ #<Capybara::Node::Element tag="h2" path="/html/body/h2">