Using Capybara for testing integration with asynchronous JavaScript

Question

Using Capybara for testing integration with asynchronous JavaScript

I am currently facing an issue with a failing Rails integration test that has me stumped. The test utilizes Capybara with Selenium as the driver.

The specific problem lies in verifying that certain page content is removed after an AJAX call is made. Essentially, a button click triggers a jQuery remove() call which should eliminate a particular section of the page. Here is a snippet of the integration testing code:

click_button("Remove stuff")
assert has_no_link?("This should be removed")

However, despite this setup, the assertion fails, indicating that the link still exists on the page.

In my attempt to troubleshoot, I've explored extending the default wait time in Capybara up to 20 seconds without success. Additionally, upon manually inspecting the source and DOM during the testing process, I noticed discrepancies. The source displayed the content while the DOM did not reveal the element using Firefox's DOM Inspector. Could this disparity be causing the issue at hand?

I find it puzzling that Capybara can detect the non-existent link within the DOM. Is it possible that Capybara is analyzing the source rather than the actual DOM structure? If so, I am unsure how to rectify this situation to ensure the successful execution of the test. Although refreshing the page may resolve the problem, it doesn't align with typical user behavior, making it an unsuitable solution to simply pass the test...

If you have any suggestions or guidance on how to tackle this challenge, I would greatly appreciate it.

Thank you!

javascript jquery ruby-on-rails selenium capybara

Answer 1

Answer №1

If you're struggling with waiting for AJAX to complete, Thoughtbot's blog has a helpful post on the topic that you can check out here. While the example is in Rspec, and it seems like you're using TestUnit, the concept can still be useful.

The solution presented works well when Capybara's default wait time isn't enough without unnecessarily long timeouts. You can adapt the code snippet below by creating a file named `wait_for_ajax.rb` in the `test/support` directory:

# Create this file in test/support/wait_for_ajax.rb
module WaitForAjax
  def wait_for_ajax
    Timeout.timeout(Capybara.default_max_wait_time) do
      loop until finished_all_ajax_requests?
    end
  end

  def finished_all_ajax_requests?
    page.evaluate_script('jQuery.active').zero?
  end
end

You have the option to include this module in individual test files as needed or explore methods outlined in this Stack Overflow post to automatically apply it every time.

To use the `wait_for_ajax` method in your tests, simply insert the line within the test case where AJAX completion needs to be ensured. For instance:

click_button("Remove stuff")
wait_for_ajax
assert has_no_link?("This should be removed")

Answer 2

If you're struggling with waiting for AJAX to complete, Thoughtbot's blog has a helpful post on the topic that you can check out here. While the example is in Rspec, and it seems like you're using TestUnit, the concept can still be useful.

The solution presented works well when Capybara's default wait time isn't enough without unnecessarily long timeouts. You can adapt the code snippet below by creating a file named `wait_for_ajax.rb` in the `test/support` directory:

# Create this file in test/support/wait_for_ajax.rb
module WaitForAjax
  def wait_for_ajax
    Timeout.timeout(Capybara.default_max_wait_time) do
      loop until finished_all_ajax_requests?
    end
  end

  def finished_all_ajax_requests?
    page.evaluate_script('jQuery.active').zero?
  end
end

You have the option to include this module in individual test files as needed or explore methods outlined in this Stack Overflow post to automatically apply it every time.

To use the `wait_for_ajax` method in your tests, simply insert the line within the test case where AJAX completion needs to be ensured. For instance:

click_button("Remove stuff")
wait_for_ajax
assert has_no_link?("This should be removed")

Answer 3

Answer №2

Previously, there was a method called wait_until that has recently been deprecated and replaced with the synchronize method.

Find out more about this change here.

You can check the new implementation of this method here.

At the moment, I am unsure of how to use it properly, but I have reached out to the author for clarification. Hopefully, we will be able to resolve this issue soon.

Answer 4

Previously, there was a method called wait_until that has recently been deprecated and replaced with the synchronize method.

Find out more about this change here.

You can check the new implementation of this method here.

At the moment, I am unsure of how to use it properly, but I have reached out to the author for clarification. Hopefully, we will be able to resolve this issue soon.

Answer 5

Answer №3

One helpful method to verify the completion of ajax requests involves utilizing the technique outlined in this article. Rather than relying on a fixed waiting time, you can leverage the $.active function associated with ajax (although not officially documented in the API but accessible) to monitor the number of active connections to a server. This way, once the count reaches zero, it indicates that the ajax request has finished:

wait_until do
  page.evaluate_script('$.active') == 0
end

If this approach proves ineffective, then the underlying problem likely lies elsewhere, as suggested by your description. In cases where changes occur solely in the DOM, ensure that javascript is enabled for your test/spec. In rspec, you can enable this with :js => true; in Cucumber, include @javascript above the scenario. Although I don't utilize rails' default tests, there should be an equivalent setting available.

Answer 6

One helpful method to verify the completion of ajax requests involves utilizing the technique outlined in this article. Rather than relying on a fixed waiting time, you can leverage the $.active function associated with ajax (although not officially documented in the API but accessible) to monitor the number of active connections to a server. This way, once the count reaches zero, it indicates that the ajax request has finished:

wait_until do
  page.evaluate_script('$.active') == 0
end

If this approach proves ineffective, then the underlying problem likely lies elsewhere, as suggested by your description. In cases where changes occur solely in the DOM, ensure that javascript is enabled for your test/spec. In rspec, you can enable this with :js => true; in Cucumber, include @javascript above the scenario. Although I don't utilize rails' default tests, there should be an equivalent setting available.

Answer 7

Answer №4

Are you first experimenting with a different function using the link before verifying its removal?

In simpler terms, is your testing process similar to this:

has_no_link = $('#id_for_link')
//.... some test
click_button("Remove stuff")
assert has_no_link?("This should be removed")

If so, then even after removing the link from the DOM using remove(), your variable still refers to it in memory.

You will need to search for the link again within the DOM to check if it has been successfully removed.

Answer 8

Are you first experimenting with a different function using the link before verifying its removal?

In simpler terms, is your testing process similar to this:

has_no_link = $('#id_for_link')
//.... some test
click_button("Remove stuff")
assert has_no_link?("This should be removed")

If so, then even after removing the link from the DOM using remove(), your variable still refers to it in memory.

You will need to search for the link again within the DOM to check if it has been successfully removed.

Answer 9

Answer №5

For a recent test scenario that required waiting for a callback triggered by streaming a YouTube video to a specific point, I found it necessary to modify the wait_until function. Here's how I adapted it:

# in my_test_helper.rb
require "timeout"
def wait_until time=0.1
    Timeout.timeout(Capybara.default_wait_time) do
        sleep(time) until result = yield
        result
    end
end

Answer 10

For a recent test scenario that required waiting for a callback triggered by streaming a YouTube video to a specific point, I found it necessary to modify the wait_until function. Here's how I adapted it:

# in my_test_helper.rb
require "timeout"
def wait_until time=0.1
    Timeout.timeout(Capybara.default_wait_time) do
        sleep(time) until result = yield
        result
    end
end

Answer 11

Answer №6

Here are a couple of strategies I came up with:

1: Verify the version of Capybara you are using and investigate any potential issues related to that version.

2: You could attempt to locate the link after clicking the button like this:

click_button("Remove stuff") find(:xpath, '//a[text()='Link should be removed').should be_false

3: Instead of using has_no_link?, try utilizing has_link? in your test script:

click_button("Remove stuff") page.has_link?("Link should be removed").should be_false

Answer 12

Here are a couple of strategies I came up with:

1: Verify the version of Capybara you are using and investigate any potential issues related to that version.

2: You could attempt to locate the link after clicking the button like this:

click_button("Remove stuff") find(:xpath, '//a[text()='Link should be removed').should be_false

3: Instead of using has_no_link?, try utilizing has_link? in your test script:

click_button("Remove stuff") page.has_link?("Link should be removed").should be_false

Answer 13

Answer №7

One way to achieve this is by manually implementing it. Here is a code snippet inspired by @shioyama's suggestion:

  def wait_for_ajax
    timer_end = Time.now + 5.seconds 
    while page.evaluate_script('$.active') != 0    
      if Time.now > timer_end
        fail "Page took more than 5 seconds to load via ajax"
      end 
      sleep 0.1
    end
  end

Answer 14

One way to achieve this is by manually implementing it. Here is a code snippet inspired by @shioyama's suggestion:

  def wait_for_ajax
    timer_end = Time.now + 5.seconds 
    while page.evaluate_script('$.active') != 0    
      if Time.now > timer_end
        fail "Page took more than 5 seconds to load via ajax"
      end 
      sleep 0.1
    end
  end

Using Capybara for testing integration with asynchronous JavaScript

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

Answer №7

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