Capybara (driver capybara-webkit) fails sporadically, succeeds over 50% of the time

Question

I have attached the log, but, basically, I've been fighting this all day. It succeeds the majority of the time, but then randomly fails with no predictable pattern.

These are very easy capybara tests, too:

    t.visit '/signup'
    t.fill_in 'user_email', :with => email
    t.fill_in 'user_password', :with => password
    t.fill_in 'user_password_confirmation', :with => password
    t.click_on 'Create Login'
    expect(page).to have_content('Welcome!')

I have no idea what could cause this. I'd appreciate any insight.

$ repeat 12 {rspec}

Randomized with seed 64607
.WARNING: The next major version of capybara-webkit will require at least version 5.0 of Qt. You're using version 4.8.7.
....

Finished in 1 minute 6 seconds (files took 1.94 seconds to load)
5 examples, 0 failures

Randomized with seed 64607


Randomized with seed 64579
WARNING: The next major version of capybara-webkit will require at least version 5.0 of Qt. You're using version 4.8.7.
.....

Finished in 1 minute 10.06 seconds (files took 2.16 seconds to load)
5 examples, 0 failures

Randomized with seed 64579


Randomized with seed 19540
.WARNING: The next major version of capybara-webkit will require at least version 5.0 of Qt. You're using version 4.8.7.
....

Finished in 1 minute 9.6 seconds (files took 2.17 seconds to load)
5 examples, 0 failures

Randomized with seed 19540


Randomized with seed 14891
WARNING: The next major version of capybara-webkit will require at least version 5.0 of Qt. You're using version 4.8.7.
.....

Finished in 1 minute 10.32 seconds (files took 2.27 seconds to load)
5 examples, 0 failures

Randomized with seed 14891


Randomized with seed 18405
WARNING: The next major version of capybara-webkit will require at least version 5.0 of Qt. You're using version 4.8.7.
..F..

Failures:

  1) User accounts Creating a new account does proceed with valid  information
     Failure/Error: expect(page).to have_content('Welcome!')

     Capybara::Webkit::NodeNotAttachedError:
       Element at 24 no longer present in the DOM
     # ./spec/features/create_account_spec.rb:24:in `block (3 levels) in <top (required)>'

Finished in 1 minute 10.47 seconds (files took 2.36 seconds to load)
5 examples, 1 failure

Failed examples:

rspec ./spec/features/create_account_spec.rb:21 # User accounts Creating a new account does proceed with valid  information

Randomized with seed 18405


Randomized with seed 44934
WARNING: The next major version of capybara-webkit will require at least version 5.0 of Qt. You're using version 4.8.7.
..F..

Failures:

  1) User accounts Creating a new account responds with an error if a password is invalid
     Failure/Error: t.visit '/signup'

     Capybara::Webkit::TimeoutError:
       Request timed out after 30 second(s)

Finished in 1 minute 37.2 seconds (files took 2.14 seconds to load)
5 examples, 1 failure

Failed examples:

rspec ./spec/features/create_account_spec.rb:34 # User accounts Creating a new account responds with an error if a password is invalid

Randomized with seed 44934


Randomized with seed 2418
WARNING: The next major version of capybara-webkit will require at least version 5.0 of Qt. You're using version 4.8.7.
.....

Finished in 1 minute 38.48 seconds (files took 2.22 seconds to load)
5 examples, 0 failures

Randomized with seed 2418


Randomized with seed 62514
WARNING: The next major version of capybara-webkit will require at least version 5.0 of Qt. You're using version 4.8.7.
..F..

Failures:

  1) User accounts Creating a new account does proceed with valid  information
     Failure/Error: expect(page).to have_content('Welcome!')

     Capybara::Webkit::NodeNotAttachedError:
       Element at 25 no longer present in the DOM
     # ./spec/features/create_account_spec.rb:24:in `block (3 levels) in <top (required)>'

Finished in 1 minute 44.84 seconds (files took 2.18 seconds to load)
5 examples, 1 failure

Failed examples:

rspec ./spec/features/create_account_spec.rb:21 # User accounts Creating a new account does proceed with valid  information

Randomized with seed 62514


Randomized with seed 61981
WARNING: The next major version of capybara-webkit will require at least version 5.0 of Qt. You're using version 4.8.7.
Request to unknown URL: https://api.stripe.com/v1/tokens?...
To block requests to unknown URLs:
  Capybara::Webkit.configure do |config|
    config.block_unknown_urls
  end
To allow just this URL:
  Capybara::Webkit.configure do |config|
    config.allow_url("https://api.stripe.com/v1/tokens?key=pk_test_ahWNI8gsTepFWYX9nnO0Kgxv&payment_user_agent=stripe.js/699b119&card[name]=Bob+Tomato&card[number]=42&card[cvc]=567&card[address_zip]=37069&card[exp_month]=1&card[exp_year]=2026&callback=sjsonp1452131002689&_method=POST&_accept_language=en-US")
  end
To allow requests to URLs from this host:
  Capybara::Webkit.configure do |config|
    config.allow_url("api.stripe.com")
  end
F....

Failures:

  1) User accounts Creating a new account does not proceed if any  information is missing
     Failure/Error: expect(page).to have_content('This Card Number Looks Invalid')
       expected to find text "This Card Number Looks Invalid" in ...
     # ./spec/features/create_account_spec.rb:18:in `block (3 levels) in <top (required)>'

Finished in 1 minute 50.89 seconds (files took 2.41 seconds to load)
5 examples, 1 failure

Failed examples:

rspec ./spec/features/create_account_spec.rb:15 # User accounts Creating a new account does not proceed if any  information is missing

Randomized with seed 61981


Randomized with seed 55263
WARNING: The next major version of capybara-webkit will require at least version 5.0 of Qt. You're using version 4.8.7.
.....

Finished in 1 minute 27.56 seconds (files took 2.26 seconds to load)
5 examples, 0 failures

Randomized with seed 55263


Randomized with seed 21927
WARNING: The next major version of capybara-webkit will require at least version 5.0 of Qt. You're using version 4.8.7.
.....

Finished in 1 minute 23.52 seconds (files took 2.22 seconds to load)
5 examples, 0 failures

Randomized with seed 21927


Randomized with seed 8605
WARNING: The next major version of capybara-webkit will require at least version 5.0 of Qt. You're using version 4.8.7.
....F

Failures:

  1) User accounts Creating a new account does not proceed if any information is missing
     Failure/Error: t.visit '/signup'

     Capybara::Webkit::TimeoutError:
       Request timed out after 30 second(s)

Finished in 1 minute 32.47 seconds (files took 2.02 seconds to load)
5 examples, 1 failure

Failed examples:

rspec ./spec/features/create_account_spec.rb:15 # User accounts Creating a new account does not proceed if any information is missing

Randomized with seed 8605

Answer 1

Sporadic errors like this are typically caused from an a timing problem in your specs. Usually from elements not existing on the page when the page took too long to load.

The easiest way I have found to fix these types of errors is to wrap your expectations in a within block . Your tests then will actually wait to find that selector used for the within block before proceeding to your expectations.

Add a within block like this

t.visit '/signup'
within "form" do
  t.fill_in 'user_email', :with => email
  t.fill_in 'user_password', :with => password
  t.fill_in 'user_password_confirmation', :with => password
  t.click_on 'Create Login'
end
expect(page).to have_content('Welcome!')