Quiet Backtrace

Quiet Backtrace suppresses the noise in your Test::Unit backtrace. It also provides hooks for you to add additional silencers and filters.

Install

sudo gem install quietbacktrace

Usage

Quiet Backtrace works by adding new attributes to Test::Unit::TestCase. By default, their values are:

self.quiet_backtrace = true
self.backtrace_silencers = [:test_unit, :gem_root, :e1]
self.backtrace_filters = [:method_name]

Silencers remove lines from the backtrace that return true for given conditions. Filters modify the output of backtrace lines.

Override the defaults by adding your own backtrace_silencers:

class Test::Unit::TestCase
  self.new_backtrace_silencer :shoulda do |line| 
    line.include? 'vendor/plugins/shoulda'
  end
  self.backtrace_silencers << :shoulda
end

Or your own backtrace_filters:

class Test::Unit::TestCase
  self.new_backtrace_filter :ruby_path do |line|
     ruby_file_path = '/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8'
     line.slice!(0..(line =~ ruby_file_path)) if (line =~ ruby_file_path)
  end
  self.backtrace_filters << :ruby_path
end

Turn Quiet Backtrace off anywhere in your test suite by setting the flag to false:

Test::Unit::TestCase.quiet_backtrace = false

Rails-specific usage

After you have installed the gem:

cd rails-app-folder/vendor/gems
gem unpack quietbacktrace

Open rails-app-folder/config/environments/test.rb and add:

require 'quietbacktrace'

Quiet Backtrace comes with an excellent Rails-specific silencer and filter. They must be added (usually in test_helper.rb) because they are not turned on by default:

class Test::Unit::TestCase
  self.backtrace_silencers << :rails_vendor
  self.backtrace_filters   << :rails_root
end

Because Quiet Backtrace works by adding attributes onto Test::Unit::TestCase, you can add and remove silencers and filters at any level in your test suite, down to the individual test.

Resources

Authors

Dan Croak (dcroak@thoughtbot.com, http://dancroak.com)
James Golick (james@giraffesoft.ca, http://jamesgolick.com)
Joe Ferris (jferris@thoughtbot.com)

Special thanks to Boston.rb for cultivating this idea at our inaugural hackfest.

Requirements

Test::Unit
aliasing.rb and attribute_accessors.rb, which are snipped from ActiveSupport and are included in the gem. They allow quiet_backtrace.rb to use alias_method_chain, cattr_accessor, and mattr_accessor.

thoughtbot