valid_entry_state_spec.rb

require 'validate_entry_state'

describe Entry_State do
  it "should be invalid without a number" do
    entry_state = Entry_State.new(nil, "PR")
    entry_state.should_not be_valid
  end
  
  it "should be invalid without a state" do
    entry_state = Entry_State.new("123456789", nil)
    entry_state.should_not be_valid
  end
  
  it "should be valid with a state and number valid" do
    entry_state = Entry_State.new("4140011229", "PR")
    entry_state.should be_valid
  end  
  
  it "should be invalid with a state or number invalid" do
    entry_state = Entry_State.new("1234546", "PR")
    entry_state.should_not be_valid
  end
  
end

validate_entry_state.rb

#Validar Inscrição Estadual de todos os estados brasileiros usando DLL do Sintegra.

require 'Win32API'

class Entry_State
  
  def initialize(number, state)
    @number = number
    @state = state
  end  
  
  def valid?
    if @number and @state      
      obj = Win32API.new("DllInscE32", "ConsisteInscricaoEstadual", ['P', 'P'], 'I')
      if obj.call(@number, @state) == 0
        true
      end      
    end
  end
  
end