Refactor into concern

app/models/account.rb

@@ -1,5 +1,5 @@
 class Account < ApplicationRecord
-  include Syncable, Monetizable, Issuable, Chartable, Enrichable, Linkable
+  include Syncable, Monetizable, Issuable, Chartable, Enrichable, Linkable, Convertible
 
   validates :name, :balance, :currency, presence: true
 

app/models/account/balance/syncer.rb

@@ -20,15 +20,11 @@ class Account::Balance::Syncer
         update_account_info
       end
 
-      sync_exchange_rates
+      account.sync_required_exchange_rates
     end
   end
 
   private
-    def sync_exchange_rates
-      Account::ExchangeRateSync.new(account).sync_rates
-    end
-
     def sync_holdings
       @holdings = Account::Holding::Syncer.new(account, strategy: strategy).sync_holdings
     end

app/models/account/convertible.rb

@@ -0,0 +1,28 @@
+module Account::Convertible
+  extend ActiveSupport::Concern
+
+  def sync_required_exchange_rates
+    unless requires_exchange_rates?
+      Rails.logger.info("No exchange rate sync needed for account #{id}")
+      return
+    end
+
+    rates = ExchangeRate.find_rates(
+      from: currency,
+      to: target_currency,
+      start_date: start_date,
+      cache: true # caches from provider to DB
+    )
+
+    Rails.logger.info("Synced #{rates.count} exchange rates for account #{id}")
+  end
+
+  private
+    def target_currency
+      family.currency
+    end
+
+    def requires_exchange_rates?
+      currency != target_currency
+    end
+end

app/models/account/exchange_rate_sync.rb

@@ -1,32 +0,0 @@
-class Account::ExchangeRateSync
-  def initialize(account)
-    @account = account
-  end
-
-  def sync_rates
-    Rails.logger.tagged("Account::ExchangeRateSync") do
-      unless needs_rate_sync?
-        Rails.logger.info("No exchange rate sync needed for account #{@account.id}")
-        return
-      end
-
-      rates = ExchangeRate.find_rates(
-        from: @account.currency,
-        to: target_currency,
-        start_date: @account.start_date,
-        cache: true # caches from provider to DB
-      )
-
-      Rails.logger.info("Synced #{rates.count} exchange rates for account #{@account.id}")
-    end
-  end
-
-  private
-    def target_currency
-      @account.family.currency
-    end
-
-    def needs_rate_sync?
-      @account.currency != target_currency
-    end
-end

test/models/account/convertible_test.rb

@@ -1,7 +1,7 @@
 require "test_helper"
 require "ostruct"
 
-class Account::ExchangeRateSyncTest < ActiveSupport::TestCase
+class Account::ConvertibleTest < ActiveSupport::TestCase
   include Account::EntriesTestHelper
 
   setup do
@@ -43,7 +43,7 @@ class Account::ExchangeRateSyncTest < ActiveSupport::TestCase
               )
 
     assert_difference "ExchangeRate.count", 7 do
-      Account::ExchangeRateSync.new(@account).sync_rates
+      @account.sync_required_exchange_rates
     end
   end
 
@@ -53,7 +53,7 @@ class Account::ExchangeRateSyncTest < ActiveSupport::TestCase
     @provider.expects(:fetch_exchange_rates).never
 
     assert_no_difference "ExchangeRate.count" do
-      Account::ExchangeRateSync.new(@account).sync_rates
+      @account.sync_required_exchange_rates
     end
   end
 end