Disallow 4 digit last_digits for 8 digit iins

Author: ugexe

lib/minfraud/components/credit_card.rb

@@ -105,8 +105,8 @@ def validate
 
         validate_telephone_country_code('bank_phone_country_code', @bank_phone_country_code)
         validate_regex('issuer_id_number', /\A(?:[0-9]{6}|[0-9]{8})\z/, @issuer_id_number)
-        validate_regex('last_digits', /\A(?:[0-9]{2}|[0-9]{4})\z/, @last_digits)
-        validate_regex('last_4_digits', /\A(?:[0-9]{2}|[0-9]{4})\z/, @last_4_digits)
+        validate_last_digits('last_digits', @last_digits, @issuer_id_number)
+        validate_last_digits('last_4_digits', @last_digits, @issuer_id_number)
         validate_string('bank_name', 255, @bank_name)
         validate_string('bank_phone_number', 255, @bank_phone_number)
         validate_string('avs_result', 1, @avs_result)

lib/minfraud/validates.rb

@@ -70,6 +70,18 @@ def validate_credit_card_token(field, value)
       end
     end
 
+    def validate_last_digits(field, value, iin)
+      return if !value
+
+      if !value.to_s.match(/\A(?:[0-9]{2}|[0-9]{4})\z/)
+        raise InvalidInputError, "The #{field} value is not valid. It must be two or four digits."
+      end
+
+      if iin.length == 8 && value.length != 2
+        raise InvalidInputError, "The #{field} value is not valid. It must be two digits when using an eight digit issuer_id_number."
+      end
+    end
+
     def validate_custom_input_value(field, value)
       return if !value
 

spec/components/credit_card_spec.rb

@@ -48,6 +48,17 @@
       end.to raise_exception(Minfraud::InvalidInputError)
     end
 
+    it 'raises an exception for invalid values (eight digit issuer_id_number + 4 digit last_digits)' do
+      expect do
+        Minfraud::Components::CreditCard.new(
+          issuer_id_number:         '12345678',
+          last_digits:              '1234',
+          token:                    'abcd',
+          was_3d_secure_successful: true,
+        )
+      end.to raise_exception(Minfraud::InvalidInputError)
+    end
+
     it 'does not raise an exception for valid values (deprecated last_4_digits)' do
       @cc = Minfraud::Components::CreditCard.new(
         issuer_id_number:         '123456',
@@ -59,15 +70,6 @@
       expect(@cc.last_digits).to be('1234')
     end
 
-    it 'does not raise an exception for valid values (eight digit issuer_id_number)' do
-      Minfraud::Components::CreditCard.new(
-        issuer_id_number:         '12345678',
-        last_4_digits:            '1234',
-        token:                    'abcd',
-        was_3d_secure_successful: true,
-      )
-    end
-
     it 'does not raise an exception for valid values (two digit last_digits)' do
       @cc = Minfraud::Components::CreditCard.new(
         issuer_id_number:         '12345678',