serverspecでMySQLの設定を検査する抹茶ー ref: http://qiita.com/udzura/items/7284742edf0f0f1164e3

mysql_conf_matcher.rb

RSpec::Matchers.define :have_mysql_entry do |entry|
  match do |subject|
    if subject.class.name == 'Serverspec::Type::File'
      @content = subject.content
      if @value
        !! @content.lines.find {|line| line =~ /^\s*#{entry}\s*=\s*#{@value}\s*$/ }
      else
        !! @content.lines.find {|line| line =~ /^\s*#{entry}\s?=/ }
      end
    else
      raise "have_mysql_entry matcher should target to file resource"
    end
  end

  chain :with_value do |value|
    @value = value
  end

  failure_message_for_should do |actual|
    if @value
      m = "expected #{actual.to_s} to have mysql entry #{entry.inspect} with value #{@value.inspect}"
      if match = @content.match(/^(\s*#{entry}\s?=.*)/)
        m << "\n    entry #{match[1].inspect} exists, but value not matched."
      end
    else
      m = "expected #{actual.to_s} to have mysql entry #{entry.inspect}"
    end
    m
  end
end

sample_spec.rb

describe file('/etc/my.cnf') do
  it { should be_file }
  it { should have_mysql_entry('default-character-set').with_value('utf8') }
end