在测试环境中等待 Websocket Rails 事件完成

Question

我在我的 Rails 应用程序中使用 Websocket Rails gem 来发送一个触发刷新部分页面的事件。一切正常，但在我的测试中（我正在使用 Rspec + Capybara + Selenium）我似乎找不到等待页面响应 Websocket 事件的方法。我在我的测试中触发事件：

WebsocketRails[@michael.id].trigger "refresh_task", {task: @michaels_task, modified_by: @archer}

该事件按以下方式绑定。 ajax 调用返回一个实际上是另一个 ajax 调用的脚本。

channel.bind('refresh_task', function(task_user) {
        var task = task_user["task"];
        var modified_by = task_user["modified_by"];
        if ($('span[data-mahi-task-id="' + task.id +'"]').length > 0) {//if the task is currently visible
            if ($('span[data-mahi-task-id="' + task.id +'"] div.modal').length > 0 ) { //the edit is open, so prompt the user 
                refresh_task = confirm(modified_by.name + " has modified this task, do you want to re-load? (if you don't re-load you risk overwriting their changes)");
            } else {
                refresh_task = true;
            }
            if (refresh_task == true) {
                //hide the modal if it exists
                $('span[data-mahi-task-id="' + task.id +'"] div.modal').modal('hide');

                //grey out the task while we load => this will get removed in ready.js
                $('span[data-mahi-task-id="' + task.id +'"]').addClass('ajax-disabled');
                // fake a "cancel" button on the update user task which will trigger a re-load of the task
                $.ajax({
                  url: "/users/" + task.created_by_id + "/tasks/" + task.id,
                  data: {task: task, update_details_cancel_button: "", _method:'put'}, //need to teel rails this is a put - not all browsers support put
                  dataType: 'script', //what format we expect the response to be - i.e. we want to execupte the resulting script
                  complete : ajaxComplete(task,modified_by),
                  method: 'POST' //not all browsers support put so send a POST with the data _method:'put' as above
                });
            }
        }
    });

一旦 ajax 启动，我可以告诉它正在运行并等待它完成，但我需要我的测试在触发事件和以某种方式启动 ajax 之间等待？

Answer 1

我通过编写一个接受代码块的辅助方法解决了这个问题。 helper 方法记录当前时间，然后在 ajax 启动事件中添加一个函数，该函数在 sessionStorage 变量中记录 ajax 启动的时间。然后我可以运行传递给该方法的代码块并等待 ajax 启动，如下所示：

def wait_for_ajax_to_start
  start_time = Time.now.to_f * 1000 #number of milliseconds
  #attach a hander on ajaxstart to store the time ajax started in a sessionStorage variable called 'ajaxStarted'
  page.evaluate_script('$(document).ajaxStart(function() {sessionStorage.ajaxStarted = $.now()})')

  #run the code block passed to this method
  yield

  #wait until the ajax has started or timeout
  Timeout.timeout(Capybara.default_wait_time) do #timeout after the default wait time
    loop until (page.evaluate_script('sessionStorage.ajaxStarted') != nil) && (page.evaluate_script('sessionStorage.ajaxStarted').to_i >= start_time)
  end
end

我这样调用辅助方法：

wait_for_ajax_to_start {
  WebsocketRails[@michael.id].trigger "refresh_task", {task: @michaels_task, modified_by: @archer}  
}

到目前为止，这似乎对我有用....

Answer 2

您的测试应该等待页面上由刷新引起的可见更改