I've always liked using the Page Object pattern to write concise, namespaced, and composeable capybara helpers:
When /^I register as a new user$/ do
NewUserPage.new(self).tap do |page|
page.visit!
page.form.fill
page.form.submit!
end
end
class PageObject
attr_reader :page
def initialize(page)
@page = page
end
end
class NewUserPage < PageObject
def visit!
page.visit new_user_path
end
def form
@form ||= UserForm.new(self)
end
end
class UserForm < PageObject
attr_reader :parent
def initialize(parent)
@parent = parent
end
def fill
page.find('[name$="[name]"]').set 'George'
page.find('[password$="[password]"]').set 'password'
end
def page
parent.page
end
def submit!
page.find('input[type=submit]').click
end
end
However, with this PORO implementation, constantly calling page in the PageObject classes can be annoying. It would be nice to call the Capybara helpers directly without having to mix in Capybara::DSL and all those rspec/capybara helpers into PageObject.
Turns out there is. And it's in the standard Ruby library.
SimpleDelegator "provides the means to delegate all supported method calls to the object passed into the constructor". So if I subclass the NewUserPage class from SimpleDelegator:
class NewUserPage < SimpleDelegator
end
And I instantiate it with the the test suite itself:
When /^I register as a new user$/ do
new_page = NewUserPage.new(self)
# ...
end
Then Capybara helpers like visit or find automatically become available to new_page! So now I can write the PageObject classes like this:
class NewUserPage < SimpleDelegator
def visit!
visit new_user_path
end
def form
@form ||= UserForm.new(self)
end
end
class UserForm < SimpleDelegator
def fill
find('[name$="[name]"]').set 'George'
find('[password$="[password]"]').set 'password'
end
def submit!
find('input[type=submit]').click
end
end
There is a gem for Capybara which uses this pattern https://github.com/natritmeyer/site_prism, it has a lot of other cool feature.