Waiting RSpec Matchers

When writing end-to-end tests there is often a necessity to wait for something to happen. Libraries like Capybara, Watir-Webdriver provide some functionality to ease it but this functionality doesn't cover all needed cases. Sometimes you need to wait for a more specific condition.

This is where this gem aims to help.

If some_name rspec matcher exists, WaitingRspecMatchers provides you become_some_name matcher that does the same as some_name matcher but also waits for that matcher to succeed.

The benefit of using this gem over solutions like wait_until, retryable, tries is that those solutions don't integrate with RSpec and thus don't provide useful enough error messages.

To install, add this line to your Gemfile and run bundle install:

gem 'waiting_rspec_matchers'

Then you should include it in e.g. spec_helper.rb:

RSpec.configure do |config|
  config.include WaitingRspecMatchers
end

• reload page until some element/text appears:

# setup Capybara
expect do
  visit 'path'
  page
end.to become_have_css('#id', wait: 0) # `expect(page).to have_css('#id', wait: 0)` is internally invoked by this gem

• check that page url is "some_string" or will become "some_string":

# setup Capybara
expect { page.current_url }.to become_eq('http://www.google.com/')

• wait for element attribute to include a specific string:

# setup Capybara
el = find('#id')
expect { el[:class] }.to become_include('some_class')

• assert that 3 requests url of which contains /path pass through proxy

# setup proxy
expect { proxy.har.entries.count { |e| e.request.url[/\/path/]} }.to become_eq(3)

You can specify a wait time (amount of time that gem will retry supplied block of code) and delay (period between retries).

You can either change default values (it will take effect for all matchers):

WaitingRspecMatchers.configure do |config|
  config.default_wait_time = 2
  config.default_delay = 0.05
end

or set it on per-matcher basis:

expect { some_code }.to become_eq(3).during(2).delay(0.05)
expect { some_code }.to become_eq(3).during(2)
expect { some_code }.to become_eq(3).delay(0.05)