How to get Rails.logger printing to the console/stdout when running rspec?

For Rails 4.x the log level is configured a bit different than in Rails 3.x

Add this to config/environment/test.rb

# Enable stdout loggerconfig.logger = Logger.new(STDOUT)# Set log levelconfig.log_level = :ERROR

The logger level is set on the logger instance from config.log_level at: https://github.com/rails/rails/blob/v4.2.4/railties/lib/rails/application/bootstrap.rb#L70

Environment variable

As a bonus, you can allow overwriting the log level using an environment variable with a default value like so:

# default :ERRORconfig.log_level = ENV.fetch("LOG_LEVEL", "ERROR")

And then running tests from shell:

# Log level :INFO (the value is uppercased in bootstrap.rb)$ LOG_LEVEL=info rake test# Log level :ERROR$ rake test

For Rails 4, see this answer.

For Rails 3.x, configure a logger in config/environments/test.rb:

config.logger = Logger.new(STDOUT)config.logger.level = Logger::ERROR

This will interleave any errors that are logged during testing to STDOUT. You may wish to route the output to STDERR or use a different log level instead.

Sending these messages to both the console and a log file requires something more robust than Ruby's built-in Logger class. The logging gem will do what you want. Add it to your Gemfile, then set up two appenders in config/environments/test.rb:

logger = Logging.logger['test']logger.add_appenders(    Logging.appenders.stdout,    Logging.appenders.file('example.log'))logger.level = :infoconfig.logger = logger

Tail the log as a background job (&) and it will interleave with rspec output.

tail -f log/test.log &bundle exec rspec