Rails5.1.3のRspecテストででたえらーの内容がわかりません。

RailsでRspecのテストを実行したら意味不明なエラーが出たのでどなたか読み解いてくれないでしょうか？エラーの解消方法が
わからないのでお願いします。

[vagrant@localhost chibi]$ bin/rspec spec/controllers/staff/top_controller_spec.rb
Running via Spring preloader in process 15544
FF...

Failures:

  1) Staff::TopController ログイン前 IPアドレスによるアクセス制限 許可
   Failure/Error: where(namespace: namespace).where(options_for(ip_address)).exists?

    ActiveRecord::StatementInvalid:
     Mysql2::Error: You have an error in your SQL syntax; check the manual tha
t corresponds to your MySQL server version for the right syntax to use near '.gs
ub(/ +/, ' ').strip) LIMIT 1' at line 4: SELECT  1 AS one FROM `allowed_sources`
 WHERE `allowed_sources`.`namespace` = 'staff' AND (
               octet1 = '0' AND octet2 = '0' AND octet3 = '0'
               AND ((octet4 = '0' AND wildcard = 0) OR wildcard = 1)
             .gsub(/ +/, ' ').strip) LIMIT 1
    # ./app/models/allowed_source.rb:48:in `include?'
     # ./app/controllers/staff/base.rb:18:in `check_source_ip_address'
     # ./spec/controllers/staff/top_controller_spec.rb:13:in `block (3 levels) i
n <top (required)>'
    # -e:1:in `<main>'
     # ------------------
     # --- Caused by: ---
     # Mysql2::Error:
     #   You have an error in your SQL syntax; check the manual that corresponds
to your MySQL server version for the right syntax to use near '.gsub(/ +/, ' ')
.strip) LIMIT 1' at line 4
   #   ./app/models/allowed_source.rb:48:in `include?'

 2）も同じ内容です。

Rspecによるテストコード

spec/controllers/staff/top_controller_spec.rb

require 'rails_helper'

describe Staff::TopController, 'ログイン前' do
  let(:staff_member) { create(:staff_member) }

  describe 'IPアドレスによるアクセス制限' do
    before do
      Rails.application.config.chibi[:restrict_ip_addresses] = true
    end

    example '許可' do
      AllowedSource.create!(namespace: 'staff', ip_address: '0.0.0.0')
      get :index
      expect(response).to render_template('staff/top/index')
    end

    example '拒否' do
      AllowedSource.create!(namespace: 'staff', ip_address: '192.168.0.*')
      get :index
      expect(response).to render_template('errors/forbidden')
    end
  end
end

describe Staff::TopController, 'ログイン後' do
  let(:staff_member) { create(:staff_member) }

  before do
    session[:staff_member_id] = staff_member.id
    session[:last_access_time] = 1.second.ago
  end

  describe '#index' do
    example '通常はstaff/top/dashboardを表示' do
      get :index
      expect(response).to render_template('staff/top/dashboard')
    end

    example '停止フラグがセットされたら強制的にログアウト' do
      staff_member.update_column(:suspended, true)
      get :index
      expect(session[:staff_member_id]).to be_nil
      expect(response).to redirect_to(staff_root_url)
    end

    example 'セッションタイムアウト' do
      session[:last_access_time] =
        Staff::Base::TIMEOUT.ago.advance(seconds: -1)
      get :index
      expect(session[:staff_member_id]).to be_nil
      expect(response).to redirect_to(staff_login_url)
    end
  end
end

失敗したと思われるコード

class AllowedSource < ActiveRecord::Base
  attr_accessor :last_octet, :_destroy
  
   before_validation do
    if last_octet
      self.last_octet.strip!
      if last_octet == '*'
        self.octet4 = 0
        self.wildcard = true
      else
        self.octet4 = last_octet
      end
    end
  end
  
  validates :octet1, :octet2, :octet3, :octet4, presence: true,
    numericality: { only_integer: true, allow_blank: true },
    inclusion: { in: 0..255, allow_blank: true }
  validates :octet4,
    uniqueness: { scope: [ :octet1, :octet2, :octet3 ], allow_blank: true }
  validates :last_octet,
    inclusion: { in: (0..255).to_a.map(&:to_s) + [ '*' ], allow_blank: true }

  after_validation do
    if last_octet
      errors[:octet4].each do |message|
        errors.add(:last_octet, message)
      end
    end
  end
  
  def ip_address=(ip_address)
    octets = ip_address.split('.')
    self.octet1 = octets[0]
    self.octet2 = octets[1]
    self.octet3 = octets[2]
    if octets[3] == '*'
      self.octet4 = 0
      self.wildcard = true
    else
      self.octet4 = octets[3]
    end
  end
  
  class << self
    def include?(namespace, ip_address)
      !Rails.application.config.chibi[:restrict_ip_addresses] ||
        where(namespace: namespace).where(options_for(ip_address)).exists?  #このあたりでエラーがでています。
    end

    private
    def options_for(ip_address)
      octets = ip_address.split('.')
      condition = %Q{
        octet1 = ? AND octet2 = ? AND octet3 = ?
        AND ((octet4 = ? AND wildcard = ?) OR wildcard = ?)  #このあたりのコードがダメなのでは？と思います。
      .gsub(/\s+/, ' ').strip}
      [ condition, *octets, false, true ]
    end
  end      
end

以上宜しくお願いします。