No terminal output with caypbara / rspec / selenium-webdriver

Question

I have been writing rspec tests using capybara and selenium-webdriver. Almost without fail, whenever I run one of these tests, the console output is gone.

For instance:

~/code/code> bundle exec rspec spec/features/interactions_spec.rb 

InteractionsSpec
~/code/code> 

Thats just about all I ever see. The browser launches, performs the action's I've coded, but I don't see the usual output.

Sometimes I'll see this as output instead (yay!):

InteractionsSpec
  login as admin works
  login as user works

Finished in 16.84 seconds (files took 7.9 seconds to load)
2 examples, 0 failures

What could be causing the output from the tests to disappear? This makes it nearly impossible to write tests - as I have no idea what has run, what has passed, what has failed, or why they have failed.

I'm using these Gems, but performing a bundle update does not change the behavior.

• capybara (2.4.4)
• capybara-screenshot (1.0.3)
• rspec (3.0.0)
• rspec-activemodel-mocks (1.0.1)
• rspec-collection_matchers (1.0.0)
• rspec-core (3.0.3)
• rspec-expectations (3.0.3)
• rspec-mocks (3.0.3)
• rspec-rails (3.0.2)
• rspec-support (3.0.3)
• selenium-webdriver (2.44.0)
• shoulda-matchers (2.6.2)

Other involved software:

• Firefox 33.1.1 (Chrome 39.0.2171.65 (64-bit) has the same behavior)
• OSX 10.9.5
• Rails 4.1.4

Update This seemed to fix the problem for a while, even with a sleep of 1ms. However, that was only a temporary fix and this problem persists.

RSpec.configure do |config|
  config.before(:each, :type => :feature) do
    sleep(0.5)
  end
end

Answer 1

Looks to me like the logger is getting silenced via a call to logger.silence() by some other thread.

When you put the sleep() in the code, then you yielded to some other thread that fixed the logging level - that's why it didn't matter how long the sleep was, it was the context switch that was fixing the issue.

When you upgraded the activesupport gem, this commit here https://github.com/rails/activerecord-session_store/commit/f92d1135fc620cb4d65239ef286b267945bbbbc6 fixes the issue (as you said). Reading that commit, notice a new threadsafe implementation of logger.silence. That's why it fixes your issue.

The old implementation of active_support/logger_silence.rb here isn't threadsafe:

require 'active_support/concern'

module LoggerSilence
  extend ActiveSupport::Concern

  included do
    cattr_accessor :silencer
    self.silencer = true
  end

  # Silences the logger for the duration of the block.
  def silence(temporary_level = Logger::ERROR)
    if silencer
      begin
        old_logger_level, self.level = level, temporary_level
        yield self
      ensure
        self.level = old_logger_level
      end
    else
      yield self
    end
  end
end

Answer 2

There seems to be a number of issues related to thread safety and race conditions in initializing the rails environment under capybara, which uses multiple threads. Rob's answer explains why it starts working (logging is fixed to be thread-save in activerecord-session_store).

It seems that these issues and commits are also related

• https://github.com/rails/rails/issues/15089
• https://github.com/jnicklas/capybara/issues/1419
• https://github.com/jnicklas/capybara/commit/a4fc9d96f705e9ac4732c5fa05ab79d947743599