Selenium driver automatically waits for AJAX requests to finish

History.txt

@@ -5,6 +5,7 @@ Release date:
 ### Added
 
 * Added DSL for acceptance tests, inspired by Luismi Cavallé's Steak [Jonas Nicklas]
+* Selenium driver automatically waits for AJAX requests to finish [mgiambalvo, Nicklas Ramhöj and Jonas Nicklas]
 
 ### Changed
 

README.rdoc

@@ -174,6 +174,11 @@ At the moment, Capybara supports Webdriver, also called Selenium 2.0, *not*
 Selenium RC. Provided Firefox is installed, everything is set up for you, and
 you should be able to start using Selenium right away.
 
+By default Capybara tried to synchronize AJAX requests, so it will wait for
+AJAX requests to finish after you've interacted with the page. You can switch
+off this behaviour by setting the driver option <tt>:resynchronize</tt> to
+<tt>false</tt>. See the section on configuring drivers.
+
 == Celerity
 
 Celerity only runs on JRuby, so you'll need to install the celerity gem under

lib/capybara/driver/selenium_driver.rb

@@ -1,6 +1,13 @@
 require 'selenium-webdriver'
 
 class Capybara::Driver::Selenium < Capybara::Driver::Base
+  DEFAULT_OPTIONS = {
+    :resynchronize => true,
+    :resynchronization_timeout => 10,
+    :browser => :firefox
+  }
+  SPECIAL_OPTIONS = [:browser, :resynchronize, :resynchronization_timeout]
+
   class Node < Capybara::Driver::Node
     def text
       native.text
@@ -26,32 +33,34 @@ class Capybara::Driver::Selenium < Capybara::Driver::Base
 
     def set(value)
       if tag_name == 'input' and type == 'radio'
-        native.click
+        click
       elsif tag_name == 'input' and type == 'checkbox'
-        native.click if value ^ native.attribute('checked').to_s.eql?("true")
+        click if value ^ native.attribute('checked').to_s.eql?("true")
       elsif tag_name == 'textarea' or tag_name == 'input'
+        resynchronize do
           native.clear
           native.send_keys(value.to_s)
         end
       end
+    end
 
     def select_option
-      native.select
+      resynchronize { native.select }
     end
 
     def unselect_option
       if select_node['multiple'] != 'multiple' and select_node['multiple'] != 'true'
         raise Capybara::UnselectNotAllowed, "Cannot unselect option from single select box."
       end
-      native.toggle if selected?
+      resynchronize { native.toggle } if selected?
     end
 
     def click
-      native.click
+      resynchronize { native.click }
     end
 
     def drag_to(element)
-      native.drag_and_drop_on(element.native)
+      resynchronize { native.drag_and_drop_on(element.native) }
     end
 
     def tag_name
@@ -76,6 +85,10 @@ class Capybara::Driver::Selenium < Capybara::Driver::Base
 
   private
 
+    def resynchronize
+      driver.resynchronize { yield }
+    end
+
     # a reference to the select node if this is an option node
     def select_node
       find('./ancestor::select').first
@@ -91,7 +104,7 @@ class Capybara::Driver::Selenium < Capybara::Driver::Base
 
   def browser
     unless @browser
-      @browser = Selenium::WebDriver.for(options[:browser] || :firefox, options.reject{|key,val| key == :browser})
+      @browser = Selenium::WebDriver.for(options[:browser], options.reject { |key,val| SPECIAL_OPTIONS.include?(key) })
       at_exit do
         @browser.quit
       end
@@ -101,7 +114,7 @@ class Capybara::Driver::Selenium < Capybara::Driver::Base
 
   def initialize(app, options={})
     @app = app
-    @options = options
+    @options = DEFAULT_OPTIONS.merge(options)
     @rack_server = Capybara::Server.new(@app)
     @rack_server.boot if Capybara.run_server
   end
@@ -128,6 +141,18 @@ class Capybara::Driver::Selenium < Capybara::Driver::Base
 
   def wait?; true; end
 
+  def resynchronize
+    if options[:resynchronize]
+      load_wait_for_ajax_support
+      yield
+      Capybara.timeout(options[:resynchronization_timeout], self, "failed to resynchronize, ajax request timed out") do
+        evaluate_script("!window.capybaraRequestsOutstanding")
+      end
+    else
+      yield
+    end
+  end
+
   def execute_script(script)
     browser.execute_script script
   end
@@ -148,12 +173,57 @@ class Capybara::Driver::Selenium < Capybara::Driver::Base
     browser.switch_to.window old_window
   end
 
-  def within_window(handle, &blk)
+  def find_window( selector )
+    original_handle = browser.window_handle
+    browser.window_handles.each do |handle|
+      browser.switch_to.window handle
+      if( selector == browser.execute_script("return window.name") ||
+          browser.title.include?(selector) ||
+          browser.current_url.include?(selector) ||
+          (selector == handle) )
+        browser.switch_to.window original_handle
+        return handle
+      end
+    end
+    raise Capybara::ElementNotFound, "Could not find a window identified by #{selector}"
+  end
+
+  def within_window(selector, &blk)
+    handle = find_window( selector )
     browser.switch_to.window(handle, &blk)
   end
 
 private
 
+  def load_wait_for_ajax_support
+    browser.execute_script <<-JS
+      window.capybaraRequestsOutstanding = 0;
+      (function() { // Overriding XMLHttpRequest
+          var oldXHR = window.XMLHttpRequest;
+
+          function newXHR() {
+              var realXHR = new oldXHR();
+
+              window.capybaraRequestsOutstanding++;
+              realXHR.addEventListener("readystatechange", function() {
+                  if( realXHR.readyState == 4 ) {
+                    setTimeout( function() {
+                      window.capybaraRequestsOutstanding--;
+                      if(window.capybaraRequestsOutstanding < 0) {
+                        window.capybaraRequestsOutstanding = 0;
+                      }
+                    }, 500 );
+                  }
+              }, false);
+
+              return realXHR;
+          }
+
+          window.XMLHttpRequest = newXHR;
+      })();
+    JS
+  end
+
   def url(path)
     rack_server.url(path)
   end

lib/capybara/spec/driver.rb

@@ -127,6 +127,42 @@ shared_examples_for "driver with javascript support" do
       @driver.evaluate_script('1+1').should == 2
     end
   end
+
+end
+
+shared_examples_for "driver with resynchronization support" do
+  before { @driver.visit('/with_js') }
+  describe "#find" do
+    context "with synchronization turned on" do
+      it "should wait for all ajax requests to finish" do
+        @driver.find('//input[@id="fire_ajax_request"]').first.click
+        @driver.find('//p[@id="ajax_request_done"]').should_not be_empty
+      end
+    end
+
+    context "with resynchronization turned off" do
+      before { @driver.options[:resynchronize] = false }
+
+      it "should not wait for ajax requests to finish" do
+        @driver.find('//input[@id="fire_ajax_request"]').first.click
+        @driver.find('//p[@id="ajax_request_done"]').should be_empty
+      end
+
+      after { @driver.options[:resynchronize] = true }
+    end
+
+    context "with short synchronization timeout" do
+      before { @driver.options[:resynchronization_timeout] = 0.1 }
+
+      it "should raise an error" do
+        expect do
+          @driver.find('//input[@id="fire_ajax_request"]').first.click
+        end.to raise_error(Capybara::TimeoutError, "failed to resynchronize, ajax request timed out")
+      end
+
+      after { @driver.options[:resynchronization_timeout] = 10 }
+    end
+  end
 end
 
 shared_examples_for "driver with header support" do

lib/capybara/spec/public/test.js

@@ -25,9 +25,14 @@ $(function() {
     }, 500);
   });
   $('#with_focus_event').focus(function() {
-    $('body').append('<p id="focus_event_triggered">Focus Event triggered</p>')
+    $('body').append('<p id="focus_event_triggered">Focus Event triggered</p>');
   });
   $('#checkbox_with_event').click(function() {
-    $('body').append('<p id="checkbox_event_triggered">Checkbox event triggered</p>')
+    $('body').append('<p id="checkbox_event_triggered">Checkbox event triggered</p>');
+  });
+  $('#fire_ajax_request').click(function() {
+    $.ajax({url: "/slow_response", context: document.body, success: function() {
+      $('body').append('<p id="ajax_request_done">Ajax request done</p>');
+    }});
   });
 });

lib/capybara/spec/test_app.rb

@@ -59,6 +59,11 @@ class TestApp < Sinatra::Base
     redirect back
   end
 
+  get '/slow_response' do
+    sleep 2
+    'Finally!'
+  end
+
   get '/set_cookie' do
     cookie_value = 'test_cookie'
     response.set_cookie('capybara', cookie_value)

lib/capybara/spec/views/with_js.erb

@@ -34,6 +34,10 @@
     <p>
       <input type="checkbox" id="checkbox_with_event"/>
     </p>
+
+    <p>
+      <input type="submit" id="fire_ajax_request" value="Fire Ajax Request"/>
+    </p>
   </body>
 </html>
 

lib/capybara/util/timeout.rb

@@ -4,7 +4,7 @@ module Capybara
     ##
     # Provides timeout similar to standard library Timeout, but avoids threads
     #
-    def timeout(seconds = 1, driver = nil, &block)
+    def timeout(seconds = 1, driver = nil, error_message = nil, &block)
       start_time = Time.now
 
       result = nil
@@ -14,7 +14,7 @@ module Capybara
 
         delay = seconds - (Time.now - start_time)
         if delay <= 0
-          raise TimeoutError
+          raise TimeoutError, error_message || "timed out"
         end
 
         driver && driver.wait_until(delay)

spec/driver/selenium_driver_spec.rb

@@ -7,6 +7,7 @@ describe Capybara::Driver::Selenium do
 
   it_should_behave_like "driver"
   it_should_behave_like "driver with javascript support"
+  it_should_behave_like "driver with resynchronization support"
   it_should_behave_like "driver with frame support"
   it_should_behave_like "driver with support for window switching"
   it_should_behave_like "driver without status code support"