Rails belongs_to, accepts_nested_attributes_for and not typical model name bug

accepts_nested_attributes_for_bug.rb

unless File.exist?('Gemfile')
  File.write('Gemfile', <<-GEMFILE)
    source 'https://rubygems.org'
    gem 'rails', github: 'rails/rails'
    gem 'arel', github: 'rails/arel'
    gem 'rack', github: 'rack/rack'
    gem 'i18n', github: 'svenfuchs/i18n'
    gem 'sqlite3'
  GEMFILE

  system 'bundle'
end

require 'bundler'
Bundler.setup(:default)

require 'active_record'
require 'minitest/autorun'
require 'logger'

# Ensure backward compatibility with Minitest 4
Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :models do |t|
    t.integer :policy_id, null: false
  end

  create_table :policies_property do |t|
    t.string :name, null: false
  end
end

module Policies
end

class Policies::Property < ActiveRecord::Base
  self.table_name = "policies_property"

  has_one :model, inverse_of: :policy
end

class Model < ActiveRecord::Base
  validates :policy, presence: true
  belongs_to :policy, inverse_of: :model, class_name: Policies::Property
  accepts_nested_attributes_for :policy
end

class BugTest < Minitest::Test
  def test_accept_nested_attributes_for
    Model.create! policy_attributes: { name: 'Hello Kity' }
  end
end

has_one :model, inverse_of: :policy, foreign_key: :policy_id fix the problem