Extract `Account` model to the dedicated file

activerecord/test/models/account.rb

+# frozen_string_literal: true
+
+class Account < ActiveRecord::Base
+  belongs_to :firm, class_name: "Company"
+  belongs_to :unautosaved_firm, foreign_key: "firm_id", class_name: "Firm", autosave: false
+
+  alias_attribute :available_credit, :credit_limit
+
+  def self.destroyed_account_ids
+    @destroyed_account_ids ||= Hash.new { |h, k| h[k] = [] }
+  end
+
+  # Test private kernel method through collection proxy using has_many.
+  def self.open
+    where("firm_name = ?", "37signals")
+  end
+
+  before_destroy do |account|
+    if account.firm
+      Account.destroyed_account_ids[account.firm.id] << account.id
+    end
+  end
+
+  validate :check_empty_credit_limit
+
+  private
+    def check_empty_credit_limit
+      errors.add("credit_limit", :blank) if credit_limit.blank?
+    end
+
+    def private_method
+      "Sir, yes sir!"
+    end
+end

activerecord/test/models/company.rb

@@ -187,37 +187,4 @@ class SpecialClient < Client
 class VerySpecialClient < SpecialClient
 end
 
-class Account < ActiveRecord::Base
-  belongs_to :firm, class_name: "Company"
-  belongs_to :unautosaved_firm, foreign_key: "firm_id", class_name: "Firm", autosave: false
-
-  alias_attribute :available_credit, :credit_limit
-
-  def self.destroyed_account_ids
-    @destroyed_account_ids ||= Hash.new { |h, k| h[k] = [] }
-  end
-
-  # Test private kernel method through collection proxy using has_many.
-  def self.open
-    where("firm_name = ?", "37signals")
-  end
-
-  before_destroy do |account|
-    if account.firm
-      Account.destroyed_account_ids[account.firm.id] << account.id
-    end
-    true
-  end
-
-  validate :check_empty_credit_limit
-
-  private
-
-    def check_empty_credit_limit
-      errors.add("credit_limit", :blank) if credit_limit.blank?
-    end
-
-    def private_method
-      "Sir, yes sir!"
-    end
-end
+require "models/account"