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Testing for javascript alerts with Cucumber & Capybara

Ruby on Rails | July 14, 2010

Using Cumcumber + Capybara to run automated testing is a TRENDY now. But you might have trouble finding a way to assert a javascript alert, for e.g. a link created by the link_to … :confirm => “Are you sure?” and similar.

Don’t worry, here is a work around to confirm Javascript alert and dialog in your Capybara tests, simply override alert and confirm methods:

Given /^I will confirm on next step$/ do
begin
evaluate_script(“window.alert = function(msg) { return true; }”)
evaluate_script(“window.confirm = function(msg) { return true; }”)
rescue Capybara::NotSupportedByDriverError
end
end

Rescue here is added in case, you run want to run your tests without javascript (e.g. default capybara driver). If you run feature without javascript simply nothing will happen.

Moreover, using this technique you can simulate moving mouse over some elements. It is useful, when you have links that appears when certain div is under the mouse cursor.

Then /^I move mouse over “([^”]*)”$/ do |label|
begin
Capybara.current_session.driver.browser.execute_script(“$(‘#{label}’).mouseover();”)
rescue Capybara::NotSupportedByDriverError
end
end

That’s it. Happy testing !