power assert in rspec

test.rb

require 'power_assert'

module RSpec
  module PowerAssert
    def power_assert(&block)
      ::PowerAssert.start(block) do |pa|
        ret = pa.yield
        unless ret
          raise RSpec::Expectations::ExpectationNotMetError, "\nPowerAssert:\n#{pa.message_proc.call}"
        end 
      end
    end
  end
end


class RSpec::Core::ExampleGroup
  include RSpec::PowerAssert
end


describe 'test' do
  it 'test' do
    power_assert {
     [1,2,3,4].include?(1) == false 
     }
  end
end

#Failures:
#
#  1) test test
#     Failure/Error: raise RSpec::Expectations::ExpectationNotMetError, "\nPowerAssert:\n#{pa.message_proc.call}"
#       
#       PowerAssert:
#            [1,2,3,4].include?(1) == false 
#                      |
#                      true
#     # ./test.rb:9:in `block in power_assert'
#     # ./test.rb:6:in `power_assert'
#     # ./test.rb:24:in `block (2 levels) in <top (required)>'
#
#Finished in 0.00101 seconds (files took 0.13324 seconds to load)
#1 example, 1 failure
#