class Rspec::Core::Configuration

def mock_framework=(use_me_to_mock)
  options[:mock_framework] = use_me_to_mock
  
  mock_framework_class = case use_me_to_mock.to_s
  when /rspec/i
    require 'rspec/core/mocking/with_rspec'
    Rspec::Core::Mocking::WithRspec
  when /mocha/i
    require 'rspec/core/mocking/with_mocha'
    Rspec::Core::Mocking::WithMocha
  when /rr/i
    require 'rspec/core/mocking/with_rr'
    Rspec::Core::Mocking::WithRR
  when /flexmock/i
    require 'rspec/core/mocking/with_flexmock'
    Rspec::Core::Mocking::WithFlexmock
  else
    require 'rspec/core/mocking/with_absolutely_nothing'
    Rspec::Core::Mocking::WithAbsolutelyNothing
  end 
  
  options[:mock_framework_class] = mock_framework_class
  Rspec::Core::ExampleGroup.send(:include, mock_framework_class)
end