Factura_spec.rb

describe "class methods" do 
  describe ".calc_amount" do 
    context "get the calc_amount of an invoice"
      it "returns 0 when the invoice status is 'Cancelado'"
      end
      it "returns 0 when the invoice amount is nil"
      end
      it "returns 0 when the invoice has policies from the current company"
      end
    end
  end
end