extract reusable logic from SalesLogVariables to independent module

app/models/derived_variables/sales_log_variables.rb

@@ -1,6 +1,8 @@
 module DerivedVariables::SalesLogVariables
+  include DerivedVariables::SharedLogic
+
   def set_derived_fields!
-    reset_invalidated_derived_values!
+    reset_invalidated_derived_values!(DEPENDENCIES)
 
     self.ethnic = 17 if ethnic_refused?
     self.mscharge = nil if no_monthly_leasehold_charges?
@@ -30,7 +32,7 @@ module DerivedVariables::SalesLogVariables
       self.uprn_known = 0
     end
 
-    set_encoded_derived_values!
+    set_encoded_derived_values!(DEPENDENCIES)
   end
 
 private
@@ -73,30 +75,6 @@ private
     },
   ].freeze
 
-  def reset_invalidated_derived_values!
-    DEPENDENCIES.each do |dependency|
-      any_conditions_changed = dependency[:conditions].any? { |attribute, _value| send("#{attribute}_changed?") }
-      next unless any_conditions_changed
-
-      previously_in_derived_state = dependency[:conditions].all? { |attribute, value| send("#{attribute}_was") == value }
-      next unless previously_in_derived_state
-
-      dependency[:derived_values].each do |derived_attribute, _derived_value|
-        Rails.logger.debug("Cleared derived #{derived_attribute} value")
-        send("#{derived_attribute}=", nil)
-      end
-    end
-  end
-
-  def set_encoded_derived_values!
-    DEPENDENCIES.each do |dependency|
-      derivation_applies = dependency[:conditions].all? { |attribute, value| send(attribute) == value }
-      if derivation_applies
-        dependency[:derived_values].each { |attribute, value| send("#{attribute}=", value) }
-      end
-    end
-  end
-
   def number_of_household_members
     return unless hholdcount.present? && jointpur.present?
 

app/models/derived_variables/shared_logic.rb

@@ -0,0 +1,27 @@
+module DerivedVariables::SharedLogic
+  private
+
+  def reset_invalidated_derived_values!(dependencies)
+    dependencies.each do |dependency|
+      any_conditions_changed = dependency[:conditions].any? { |attribute, _value| send("#{attribute}_changed?") }
+      next unless any_conditions_changed
+
+      previously_in_derived_state = dependency[:conditions].all? { |attribute, value| send("#{attribute}_was") == value }
+      next unless previously_in_derived_state
+
+      dependency[:derived_values].each do |derived_attribute, _derived_value|
+        Rails.logger.debug("Cleared derived #{derived_attribute} value")
+        send("#{derived_attribute}=", nil)
+      end
+    end
+  end
+
+  def set_encoded_derived_values!(dependencies)
+    dependencies.each do |dependency|
+      derivation_applies = dependency[:conditions].all? { |attribute, value| send(attribute) == value }
+      if derivation_applies
+        dependency[:derived_values].each { |attribute, value| send("#{attribute}=", value) }
+      end
+    end
+  end
+end