Ruby Light #5

This is a remix of Ruby Light #1, done better (IMHO):

test/lib/redirect_io.rb

require 'stringio'

module RedirectIo
  def setup
    $stderr = @stderr = StringIO.new
    $stdin = @stdin = StringIO.new
    $stdout = @stdout = StringIO.new
    super
  end

  def teardown
    $stderr = STDERR
    $stdin = STDIN
    $stdout = STDOUT
    super
  end
end

test/unit/timestamp_logger_test.rb

require 'test_helper'
require 'lib/generic_test_helper.rb'  # from Ruby Light #3
require 'lib/redirect_io'

class TimestampLoggerTest < Test::Unit::TestCase
  include GenericTestHelper
  include RedirectIo

  LOG_LEVELS = [:error, :warn, :info, :debug]

  def setup
    super  # RedirectIO.setup needs to run

    @logger = TimestampLogger.new $stdout
    @logger.level = Logger::DEBUG
  end

  def test_timestamps
    LOG_LEVELS.each do |level|
      @logger.send level, 'foo'
    end

    @stdout.string.split("\n").each do |line|
      assert_match /^#{TIMESTAMP_MATCHER} /, line
    end
  end

  def test_labels
    LOG_LEVELS.each do |level|
      @logger.send level, 'foo'
    end

    [:error, :warn].each do |level|
      assert_match /^#{TIMESTAMP_MATCHER} \[#{level.to_s.upcase}\] /, @stdout.string
    end
  end