Cucumber + Capybara driver gotchas

Cucumber and Capybara has always been our best buddies when it comes to writing integration tests. We use it quite actively on most of our projects. The power of Capybara is that it gives you options for several browser simulators, equipping you with a flexible toolkit for testing all parts of your application, from the simplest to the most complex pages and also with javascript heavy pages.

Capybara comes with “rack_test” as the default driver which doesn’t support javascript. I am not going to talk much about which driver to choose, it is upto you based on your need. You can change which driver you want to use in features/support/env.rb. It can be quite confusing when you find out there are 3 different Capybara settings can play around different drivers while running the test.

#Driver settings
Capybara.default_driver(uses rack_test as default)
Capybara.javascript_driver(uses selenium as default)
Capybara.current_driver

#features/sample.feature
Scenario: Creating a user
Given I go to the new user page
And I fill in “Name” with “TDD Ninja”
And I fill in “Email” with “gmail@ninja.com”
And I press “Create”
Then I should see “User created”

@javascript
Scenario: AJAX pagination
Given 10 blogs exist
When I go to the blogs page
Then I should see 5 blogs
When I follow “More”
Then I should see 10 blogs

In the above example, the first scenario runs with ‘rack_test’ and the second scenario runs with “selenium”. Suppose you want to set :webkit as your javascript driver, all you have to do is to set

Capybara.javascript_driver = :webkit

And from then on whenever you use @javascript in your scenario, Capybara will use :webkit as its javascript_driver instead of :selenium. Capybara also allows you to change your driver temporarily using Capybara.current_driver setting.

Capybara.current_driver = :webkit # temporarily select different driver
... tests ...
Capybara.use_default_driver # switch back to default driver

Please note that switching between drivers will create a new session, so make sure where you switch! The ideal place its to switch in the Before hook. Capybara makes it really convenient to switch between the drivers. Apart from that you can also tweek with your own settings using the API it exposes. This is how we tweeked and made selenium to use chrome.

#features/support/env.rb

Capybara.register_driver :selenium_chrome do |app|
Capybara::Selenium::Driver.new(app, :browser => :chrome)
end

Capybara.javascript_driver = :selenium_chrome

There are tons of other information in Selenium wiki.