Subclass proc to add a custom inspect method, add a class method to create a curried instance

less_than_proc.rb

class LessThanProc < Proc
  attr_accessor :present

  def self.with(present)
    pv = Gem::Version.new(present.dup)
    lt = self.new { |required| pv < Gem::Version.new(required) }
    lt.present = present
    return lt
  end

  def inspect
    "\"=< #{present.to_s}\""
  end
end

Usage:

RSpec.configure do |c|
  c.filter_run_excluding :ruby => LessThanProc.new(RUBY_VERSION)
end