Extract mismatch validator to separate class

#569

app/validators/contact/ident/mismatch_validator.rb

@@ -0,0 +1,20 @@
+class Contact::Ident::MismatchValidator < ActiveModel::Validator
+  Mismatch = Struct.new(:type, :country)
+
+  def self.mismatches
+    [
+      Mismatch.new('birthday', Country.new('EE')),
+    ]
+  end
+
+  def validate(record)
+    record.errors.add(:base, :mismatch, type: record.type, country: record.country) if mismatched?(record)
+  end
+
+  private
+
+  def mismatched?(record)
+    mismatch = Mismatch.new(record.type, record.country)
+    self.class.mismatches.include?(mismatch)
+  end
+end