Capybara::SlowFinderErrors

Raises an error when you use a capybara finder and it times out.

The goal of this gem is to aid in discovering errors in capybara usage to help speed up your test suite.

Example

If you do:

refute page.has_content?("An Error Occurred")

To make sure there's no error on the page, the full timeout will be reached because has_content? waits for the content to appear. The correct usage is:

assert page.has_no_content?("An Error Occurred")

Which would evaluate quickly.

This gem will raise a Capybara::SlowFinderError whenever the first situation occurs. In fact, it raises the error any time a Capybara synchronized piece of code reaches a timeout.

Installation

Add this line to your application's Gemfile:

gem 'capybara-slow_finder_errors'

And then execute:

$ bundle

Or install it yourself as:

$ gem install capybara-slow_finder_errors

Usage

Run your test suite as usual. If you have any slow finders, you'll get a stack trace like this:

Capybara::SlowFinderError (Capybara::SlowFinderError)
/path/to/capybara-slow_finder_errors/lib/capybara/slow_finder_errors.rb:11:in `rescue in synchronize_with_timeout_error'
/path/to/capybara-slow_finder_errors/lib/capybara/slow_finder_errors.rb:7:in `synchronize_with_timeout_error'
./features/support/signed_in_user.rb:31:in `signed_in?'
./features/support/user_helper.rb:59:in `sign_in_as'
features/configuring_a_project.feature:6:in `Given I am signed in as "herbert@awesomestartup.com"'

execution expired (Timeout::Error)
/path/to/.gems/gems/poltergeist-1.5.1/lib/capybara/poltergeist/web_socket_server.rb:72:in `select'
/path/to/.gems/gems/poltergeist-1.5.1/lib/capybara/poltergeist/web_socket_server.rb:72:in `receive'
/path/to/.gems/gems/poltergeist-1.5.1/lib/capybara/poltergeist/web_socket_server.rb:85:in `send'
/path/to/.gems/gems/poltergeist-1.5.1/lib/capybara/poltergeist/server.rb:33:in `send'
/path/to/.gems/gems/poltergeist-1.5.1/lib/capybara/poltergeist/browser.rb:270:in `command'
/path/to/.gems/gems/poltergeist-1.5.1/lib/capybara/poltergeist/browser.rb:106:in `evaluate'
/path/to/.gems/gems/poltergeist-1.5.1/lib/capybara/poltergeist/driver.rb:130:in `evaluate_script'
/path/to/.gems/gems/capybara-2.4.4/lib/capybara/session.rb:527:in `evaluate_script'
...

If you look at the lines below the gem's trace, you'll see that the slow finder is in signed_in_user.rb on line 31 in the signed_in? method. Just follow those traces and clean up your code!

RSpec

If you're using RSpec and the matchers provided by Capybara like:

expect(page).to_not have_content("abc")

then Capybara is already telling RSpec to use the negated method (has_no_content?) and thus Capybara is not waiting for the timeout before continuing.

Common Fixes

This section will hopefully grow as people contribute common situations and fixes.

Inverted Finder

Replace refute page.has_content?("abc") with assert page.has_no_content?("abc").

Boolean Finder

A method that returns a boolean shouldn't use a waiting finder. So:

def signed_in?
  page.has_content?("Sign out")
end

Returns true if they are signed in, but it waits a full timeout before returning false. Instead, perform a waiting finder for content that is always present (to ensure the page is loaded) then use a quick finder that doesn't wait:

def signed_in?
  page.has_content?("Dashboard")
  page.has_css?('a', :text => 'Home', :wait => false)
end

Contributing

Fork it https://github.com/ngauthier/capybara-slow_finder_errors/fork
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create a new Pull Request

ngauthier/capybara-slow_finder_errors