Module: ActiveSupport::LogSubscriber::TestHelper

Defined in:
activesupport/lib/active_support/log_subscriber/test_helper.rb

Overview

Provides some helpers to deal with testing log subscribers by setting up notifications. Take for instance Active Record subscriber tests:

class SyncLogSubscriberTest < ActiveSupport::TestCase
  include ActiveSupport::LogSubscriber::TestHelper

  def setup
    ActiveRecord::LogSubscriber.attach_to(:active_record)
  end

  def test_basic_query_logging
    Developer.all
    wait
    assert_equal 1, @logger.logged(:debug).size
    assert_match(/Developer Load/, @logger.logged(:debug).last)
    assert_match(/SELECT \* FROM "developers"/, @logger.logged(:debug).last)
  end
end

All you need to do is to ensure that your log subscriber is added to Rails::Subscriber, as in the second line of the code above. The test helpers are responsible for setting up the queue, subscriptions and turning colors in logs off.

The messages are available in the @logger instance, which is a logger with limited powers (it actually does not send anything to your output), and you can collect them doing @logger.logged(level), where level is the level used in logging, like info, debug, warn and so on.

Defined Under Namespace

Classes: MockLogger

Instance Method Summary (collapse)

Instance Method Details

- (Object) set_logger(logger)

Overwrite if you use another logger in your log subscriber:

def logger
  ActiveRecord::Base.logger = @logger
end


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# File 'activesupport/lib/active_support/log_subscriber/test_helper.rb', line 96

def set_logger(logger)
  ActiveSupport::LogSubscriber.logger = logger
end

- (Object) setup



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# File 'activesupport/lib/active_support/log_subscriber/test_helper.rb', line 36

def setup
  @logger   = MockLogger.new
  @notifier = ActiveSupport::Notifications::Fanout.new

  ActiveSupport::LogSubscriber.colorize_logging = false

  @old_notifier = ActiveSupport::Notifications.notifier
  set_logger(@logger)
  ActiveSupport::Notifications.notifier = @notifier
end

- (Object) teardown



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# File 'activesupport/lib/active_support/log_subscriber/test_helper.rb', line 47

def teardown
  set_logger(nil)
  ActiveSupport::Notifications.notifier = @old_notifier
end

- (Object) wait

Wait notifications to be published.



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# File 'activesupport/lib/active_support/log_subscriber/test_helper.rb', line 86

def wait
  @notifier.wait
end