require 'gen/test'
require 'contracts'
require 'contracts/gen'

Sum = lambda { |xs| xs.reduce(:+) }

C = Contracts

class SumTest < Minitest::Test
  include Gen::Test

  def test_sum_for_all_arrays_of_integers
    for_all C::ArrayOf[Integer] do |xs|
      y = Sum[xs]
      assert_equal(y, xs.reduce(:+))
    end
  end
end

gem 'contracts-gen'