Why do I get blank pages with Capybara-webkit, but not with the standard (non-JS) driver

Question

My Rspec + Capybara integration tests were working fine until I started trying to interact with Javascript-dependent interface elements using Capybara-Webkit.

When I try to use Capybara-Webkit, I get blank pages at the save_and_open_line below. Why?

/spec/features/area_spec.rb:

require 'spec_helper'
describe "Area" do
  ...
  describe "Admin" do
    ...  
    before(:each) do
      Capybara.current_driver = :webkit
      @virginia = User.create(
        :username => "Virginia", 
        :password => "password", 
        :password_confirmation => "password", 
        :email => "[email protected]")
      @admin = Role.create(:name => "admin")    
      @assignment = Assignment.create(user_id: @virginia.id, role_id: @admin.id)
      visit login_path
      fill_in 'user_session_username', :with => @virginia.username
      fill_in 'user_session_password', :with => @virginia.password
      click_on 'submit_user_session'
      visit report_path(@report)
      save_and_open_page
      page.find('#nav_reports').trigger(:mouseover)
      ...
    end
    ...
  end
  ...
end

/spec/spec_helper.rb:

require 'rubygems'
require 'spork'
require 'database_cleaner'
Spork.prefork do
end
Spork.each_run do
end
ENV["RAILS_ENV"] ||= 'test'
require File.expand_path("../../config/environment", __FILE__)
require 'rspec/rails'
require 'capybara/rspec'
require 'capybara/rails' 
require 'capybara/dsl' 
Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}
RSpec.configure do |config|
  config.mock_with :rspec
  config.fail_fast = true
  config.fixture_path = "#{::Rails.root}/spec/fixtures"
  config.before(:each) { ActionMailer::Base.deliveries.clear }
  config.use_instantiated_fixtures = false 
  config.include(Capybara, :type => :integration)
  Capybara.javascript_driver = :webkit
  config.use_transactional_fixtures = false
  config.before(:suite) do
    DatabaseCleaner.clean_with :truncation
  end
  config.before(:each) do
    if example.metadata[:js]
      DatabaseCleaner.strategy = :truncation
    else
      DatabaseCleaner.strategy = :transaction
    end
    DatabaseCleaner.start
  end
  config.after(:each) do
    DatabaseCleaner.clean
  end
end

When I remove Capybara.current_driver = :webkit from area_spec.rb (but leave the Webkit related code in spec_helper.rb), the page generated by save_and_open_page is not empty, but I get the following error at the Rspec command line:

Failure/Error: page.find('#nav_reports').trigger(:mouseover)
     Capybara::NotSupportedByDriverError:
       Capybara::NotSupportedByDriverError

Initially I tried adding :js => :true to the before block ... do, but Rspec kept rejecting my syntax. When I add :js => true to the first it ... do block to be covered by the before ... do block, I still get a blank page at save_and_open_page, but the error at the Rspec command line changes to:

Failure/Error: page.find('#nav_reports').trigger(:mouseover)
     Capybara::Webkit::NodeNotAttachedError:
       Capybara::Webkit::NodeNotAttachedError

When I move Capybara.javascript_driver = :webkit up a level in the spec_helper.rb file, out of the Rspec.configure do block, I get the same error.

When I cut every line from the before ... do block and paste it into the first it ... do block that it was meant to cover, I get the same error.

When I set config.use_transactional_fixtures = true and remove all Webkit-related code, the spec works, except of course for page.find('#nav_reports').trigger(:mouseover), which needs a Javascript driver.

UPDATE: I inserted page.current_path.should == report_path(@report) before the save_and_open_page and discovered that something about Capybara-Webkit is stopping my visit report_path(@report) from working. (It works fine when I don't try to test Javascript-dependent interface elements with Capybara-Webkit.) Error code is:

 Failure/Error: page.current_path.should == report_path(@report)
       expected: "/reports/3"
            got: nil (using ==) 

FURTHER UPDATE: I've found that when I use Capybara-Webkit, Rspec has trouble finding the @report object, even when I move my @report = Report.create(...) statement right up to the line just before visit report_path(@report). The full test log is below:

 Marker - 19/12/2012 11:55:45 AM
Connecting to database specified by database.yml
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ActiveRecord::RecordNotFound - Couldn't find Report with id=1:
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  /Users/steven/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
  /Users/steven/.rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'

  [1m[36m (1.7ms)[0m  [1mALTER TABLE "references" ENABLE TRIGGER ALL;ALTER TABLE "variants" ENABLE TRIGGER ALL;ALTER TABLE "veracities" ENABLE TRIGGER ALL;ALTER TABLE "goods" ENABLE TRIGGER ALL;ALTER TABLE "values" ENABLE TRIGGER ALL;ALTER TABLE "orders" ENABLE TRIGGER ALL;ALTER TABLE "reports" ENABLE TRIGGER ALL;ALTER TABLE "roles" ENABLE TRIGGER ALL;ALTER TABLE "users" ENABLE TRIGGER ALL;ALTER TABLE "areas" ENABLE TRIGGER ALL;ALTER TABLE "schema_migrations" ENABLE TRIGGER ALL;ALTER TABLE "ijoins" ENABLE TRIGGER ALL;ALTER TABLE "fields" ENABLE TRIGGER ALL;ALTER TABLE "footnotes" ENABLE TRIGGER ALL;ALTER TABLE "gjoins" ENABLE TRIGGER ALL;ALTER TABLE "heuristics" ENABLE TRIGGER ALL;ALTER TABLE "assignments" ENABLE TRIGGER ALL;ALTER TABLE "categories" ENABLE TRIGGER ALL;ALTER TABLE "industries" ENABLE TRIGGER ALL;ALTER TABLE "markets" ENABLE TRIGGER ALL;ALTER TABLE "mjoins" ENABLE TRIGGER ALL[0m

Answer 1

Probably not the right answer, but just in case anyone else googles this answer like me, looking for ideas:

I had forgotten the forward slash at the front of my visit url. For some reason the default rack driver was fine about that, but my JS drivers weren't (both capybara-webkit and poltergeist).