Refactor dynamic validation, test for it

app/models/domain.rb

@@ -119,8 +119,9 @@ class Domain < ActiveRecord::Base
   ### VALIDATIONS ###
 
   def validate_nameservers_count
-    sg = SettingGroup.find_by(code: SettingGroup::DOMAIN_VALIDATION_CODE)
-    min, max = sg.get(:ns_min_count).to_i, sg.get(:ns_max_count).to_i
+    sg = SettingGroup.domain_validation
+    min, max = sg.setting(:ns_min_count).value.to_i, sg.setting(:ns_max_count).value.to_i
+
     unless nameservers.length.between?(min, max)
       errors.add(:nameservers, :out_of_range, {min: min, max: max})
     end
@@ -152,7 +153,7 @@ class Domain < ActiveRecord::Base
   end
 
   def epp_code_map
-    domain_validation_sg = SettingGroup.find_by(code: SettingGroup::DOMAIN_VALIDATION_CODE)
+    domain_validation_sg = SettingGroup.domain_validation
 
     {
       '2302' => [ # Object exists
@@ -165,7 +166,7 @@ class Domain < ActiveRecord::Base
         [:valid_to, :epp_exp_dates_do_not_match]
       ],
       '2004' => [ # Parameter value range error
-        [:nameservers, :out_of_range, {min: domain_validation_sg.get(:ns_min_count), max: domain_validation_sg.get(:ns_max_count)}],
+        [:nameservers, :out_of_range, {min: domain_validation_sg.setting(:ns_min_count).value, max: domain_validation_sg.setting(:ns_max_count).value}],
         [:period, :out_of_range]
       ],
       '2303' => [ # Object does not exist

app/models/setting_group.rb

@@ -3,10 +3,13 @@ class SettingGroup < ActiveRecord::Base
 
   accepts_nested_attributes_for :settings
 
-  DOMAIN_VALIDATION_CODE = 'domain_validation'
+  def setting(key)
+    settings.find_by(code: key.to_s)
+  end
 
-  def get(key)
-    s = settings.find_by(code: key.to_s)
-    s.try(:value)
+  class << self
+    def domain_validation
+      find_by(code: 'domain_validation')
+    end
   end
 end

spec/models/domain_spec.rb

@@ -48,6 +48,19 @@ describe Domain do
         admin_contacts: ["Admin contact is missing"],
         nameservers: ["Nameservers count must be between 1-13"]
       })
+
+      sg = SettingGroup.domain_validation
+      min = sg.setting(:ns_min_count)
+      max = sg.setting(:ns_max_count)
+
+      min.value = 2
+      min.save
+
+      max.value = 7
+      max.save
+
+      expect(d.valid?).to be false
+      expect(d.errors.messages[:nameservers]).to eq(['Nameservers count must be between 2-7'])
     end
 
     it 'does not create a reserved domain' do