diff --git a/.rubocop.yml b/.rubocop.yml
index d6f9cbb716..635e1ed131 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -41,6 +41,9 @@ Metrics/PerceivedComplexity:
 Style/AccessModifierIndentation:
   EnforcedStyle: outdent
 
+Style/Alias:
+  Enabled: false
+
 Style/CollectionMethods:
   PreferredMethods:
     map:      'collect'
@@ -76,7 +79,8 @@ Style/RaiseArgs:
 Style/SpaceInsideHashLiteralBraces:
   EnforcedStyle: no_space
 
-Style/TrailingComma:
+Style/TrailingCommaInArguments:
   EnforcedStyleForMultiline: 'comma'
 
-
+Style/TrailingCommaInLiteral:
+  EnforcedStyleForMultiline: 'comma'
diff --git a/Gemfile b/Gemfile
index 58441bc7c9..50ed340519 100644
--- a/Gemfile
+++ b/Gemfile
@@ -43,7 +43,7 @@ group :test do
   gem 'pundit'
   gem 'rack-cache', require: 'rack/cache'
   gem 'rspec-rails', '>= 2.14'
-  gem 'rubocop', '~> 0.31.0'
+  gem 'rubocop', '~> 0.41.2'
   gem 'simplecov', '>= 0.9', require: false
   gem 'timecop', '>= 0.5'
 
diff --git a/app/controllers/rails_admin/application_controller.rb b/app/controllers/rails_admin/application_controller.rb
index 6a6712d4cc..9e2178eddb 100644
--- a/app/controllers/rails_admin/application_controller.rb
+++ b/app/controllers/rails_admin/application_controller.rb
@@ -21,13 +21,13 @@ class ApplicationController < Config.parent_controller.constantize
 
     def get_model
       @model_name = to_model_name(params[:model_name])
-      fail(RailsAdmin::ModelNotFound) unless (@abstract_model = RailsAdmin::AbstractModel.new(@model_name))
-      fail(RailsAdmin::ModelNotFound) if (@model_config = @abstract_model.config).excluded?
+      raise(RailsAdmin::ModelNotFound) unless (@abstract_model = RailsAdmin::AbstractModel.new(@model_name))
+      raise(RailsAdmin::ModelNotFound) if (@model_config = @abstract_model.config).excluded?
       @properties = @abstract_model.properties
     end
 
     def get_object
-      fail(RailsAdmin::ObjectNotFound) unless (@object = @abstract_model.get(params[:id]))
+      raise(RailsAdmin::ObjectNotFound) unless (@object = @abstract_model.get(params[:id]))
     end
 
     def to_model_name(param)
diff --git a/app/controllers/rails_admin/main_controller.rb b/app/controllers/rails_admin/main_controller.rb
index f54602e214..49915c7e4d 100644
--- a/app/controllers/rails_admin/main_controller.rb
+++ b/app/controllers/rails_admin/main_controller.rb
@@ -93,7 +93,7 @@ def sanitize_params_for!(action, model_config = @model_config, target_params = p
       return unless target_params.present?
       fields = visible_fields(action, model_config)
       allowed_methods = fields.collect(&:allowed_methods).flatten.uniq.collect(&:to_s) << 'id' << '_destroy'
-      fields.each { |field|  field.parse_input(target_params) }
+      fields.each { |field| field.parse_input(target_params) }
       target_params.slice!(*allowed_methods)
       target_params.permit! if target_params.respond_to?(:permit!)
       fields.select(&:nested_form).each do |association|
@@ -110,7 +110,7 @@ def handle_save_error(whereto = :new)
 
       respond_to do |format|
         format.html { render whereto, status: :not_acceptable }
-        format.js   { render whereto, layout: false, status: :not_acceptable  }
+        format.js   { render whereto, layout: false, status: :not_acceptable }
       end
     end
 
diff --git a/app/helpers/rails_admin/application_helper.rb b/app/helpers/rails_admin/application_helper.rb
index 1b08dec4c0..2ef3e967bc 100644
--- a/app/helpers/rails_admin/application_helper.rb
+++ b/app/helpers/rails_admin/application_helper.rb
@@ -47,8 +47,8 @@ def logout_path
       if defined?(Devise)
         scope = Devise::Mapping.find_scope!(_current_user)
         main_app.send("destroy_#{scope}_session_path") rescue false
-      else
-        main_app.logout_path if main_app.respond_to?(:logout_path)
+      elsif main_app.respond_to?(:logout_path)
+        main_app.logout_path
       end
     end
 
diff --git a/app/helpers/rails_admin/form_builder.rb b/app/helpers/rails_admin/form_builder.rb
index 0e39a5bc63..baf0877bad 100644
--- a/app/helpers/rails_admin/form_builder.rb
+++ b/app/helpers/rails_admin/form_builder.rb
@@ -20,10 +20,17 @@ def generate(options = {})
     end
 
     def fieldset_for(fieldset, nested_in)
-      return unless (fields = fieldset.with(form: self, object: @object, view: @template, controller: @template.controller).visible_fields).length > 0
+      fields = fieldset.with(
+        form: self,
+        object: @object,
+        view: @template,
+        controller: @template.controller,
+      ).visible_fields
+      return if fields.empty?
+
       @template.content_tag :fieldset do
         contents = []
-        contents << @template.content_tag(:legend, %(<i class="icon-chevron-#{(fieldset.active? ? 'down' : 'right')}"></i> #{fieldset.label}).html_safe, style: "#{fieldset.name == :default ? 'display:none' : ''}")
+        contents << @template.content_tag(:legend, %(<i class="icon-chevron-#{(fieldset.active? ? 'down' : 'right')}"></i> #{fieldset.label}).html_safe, style: fieldset.name == :default ? 'display:none' : '')
         contents << @template.content_tag(:p, fieldset.help) if fieldset.help.present?
         contents << fields.collect { |field| field_wrapper_for(field, nested_in) }.join
         contents.join.html_safe
diff --git a/app/helpers/rails_admin/main_helper.rb b/app/helpers/rails_admin/main_helper.rb
index 59816c7b86..1976f91510 100644
--- a/app/helpers/rails_admin/main_helper.rb
+++ b/app/helpers/rails_admin/main_helper.rb
@@ -63,7 +63,7 @@ def ordered_filter_string
         filter_name = filter_for_field.keys.first
         filter_hash = filter_for_field.values.first
         unless (field = filterable_fields.find { |f| f.name == filter_name.to_sym })
-          fail "#{filter_name} is not currently filterable; filterable fields are #{filterable_fields.map(&:name).join(', ')}"
+          raise "#{filter_name} is not currently filterable; filterable fields are #{filterable_fields.map(&:name).join(', ')}"
         end
         case field.type
         when :enum
diff --git a/config/initializers/active_record_extensions.rb b/config/initializers/active_record_extensions.rb
index a596845ceb..3dcc266d49 100644
--- a/config/initializers/active_record_extensions.rb
+++ b/config/initializers/active_record_extensions.rb
@@ -6,11 +6,11 @@ def self.rails_admin(&block)
       end
 
       def rails_admin_default_object_label_method
-        self.new_record? ? "new #{self.class}" : "#{self.class} ##{id}"
+        new_record? ? "new #{self.class}" : "#{self.class} ##{id}"
       end
 
       def safe_send(value)
-        if self.has_attribute?(value)
+        if has_attribute?(value)
           read_attribute(value)
         else
           send(value)
diff --git a/gemfiles/rails_4.0.gemfile b/gemfiles/rails_4.0.gemfile
index e5e8012930..21c7c5484a 100644
--- a/gemfiles/rails_4.0.gemfile
+++ b/gemfiles/rails_4.0.gemfile
@@ -49,7 +49,7 @@ group :test do
   gem "pundit"
   gem "rack-cache", :require => "rack/cache"
   gem "rspec-rails", ">= 2.14"
-  gem "rubocop", "~> 0.31.0"
+  gem "rubocop", "~> 0.41.2"
   gem "simplecov", ">= 0.9", :require => false
   gem "timecop", ">= 0.5"
 
diff --git a/gemfiles/rails_4.1.gemfile b/gemfiles/rails_4.1.gemfile
index 4d655cd400..cc01b69436 100644
--- a/gemfiles/rails_4.1.gemfile
+++ b/gemfiles/rails_4.1.gemfile
@@ -47,7 +47,7 @@ group :test do
   gem "pundit"
   gem "rack-cache", :require => "rack/cache"
   gem "rspec-rails", ">= 2.14"
-  gem "rubocop", "~> 0.31.0"
+  gem "rubocop", "~> 0.41.2"
   gem "simplecov", ">= 0.9", :require => false
   gem "timecop", ">= 0.5"
 
diff --git a/gemfiles/rails_4.2.gemfile b/gemfiles/rails_4.2.gemfile
index a18e1919ad..ad9b04b0b0 100644
--- a/gemfiles/rails_4.2.gemfile
+++ b/gemfiles/rails_4.2.gemfile
@@ -48,7 +48,7 @@ group :test do
   gem "pundit"
   gem "rack-cache", :require => "rack/cache"
   gem "rspec-rails", ">= 2.14"
-  gem "rubocop", "~> 0.31.0"
+  gem "rubocop", "~> 0.41.2"
   gem "simplecov", ">= 0.9", :require => false
   gem "timecop", ">= 0.5"
 
diff --git a/gemfiles/rails_5.0.gemfile b/gemfiles/rails_5.0.gemfile
index 3a58dcfaf8..114127fc77 100644
--- a/gemfiles/rails_5.0.gemfile
+++ b/gemfiles/rails_5.0.gemfile
@@ -47,7 +47,7 @@ group :test do
   gem "pundit"
   gem "rack-cache", :require => "rack/cache"
   gem "rspec-rails", ">= 2.14"
-  gem "rubocop", "~> 0.31.0"
+  gem "rubocop", "~> 0.41.2"
   gem "simplecov", ">= 0.9", :require => false
   gem "timecop", ">= 0.5"
 
diff --git a/lib/rails_admin/abstract_model.rb b/lib/rails_admin/abstract_model.rb
index e1585a4bbf..2451c45cb0 100644
--- a/lib/rails_admin/abstract_model.rb
+++ b/lib/rails_admin/abstract_model.rb
@@ -147,7 +147,7 @@ def build_statement_for_type_generic
       end
 
       def build_statement_for_type
-        fail('You must override build_statement_for_type in your StatementBuilder')
+        raise('You must override build_statement_for_type in your StatementBuilder')
       end
 
       def build_statement_for_integer_decimal_or_float
@@ -185,11 +185,11 @@ def build_statement_for_datetime_or_timestamp
       end
 
       def unary_operators
-        fail('You must override unary_operators in your StatementBuilder')
+        raise('You must override unary_operators in your StatementBuilder')
       end
 
       def range_filter(_min, _max)
-        fail('You must override range_filter in your StatementBuilder')
+        raise('You must override range_filter in your StatementBuilder')
       end
 
       class FilteringDuration
diff --git a/lib/rails_admin/adapters/active_record.rb b/lib/rails_admin/adapters/active_record.rb
index 494fdc26c6..999fe65ee3 100644
--- a/lib/rails_admin/adapters/active_record.rb
+++ b/lib/rails_admin/adapters/active_record.rb
@@ -6,7 +6,7 @@
 module RailsAdmin
   module Adapters
     module ActiveRecord
-      DISABLED_COLUMN_TYPES = [:tsvector, :blob, :binary, :spatial, :hstore, :geometry]
+      DISABLED_COLUMN_TYPES = [:tsvector, :blob, :binary, :spatial, :hstore, :geometry].freeze
 
       def new(params = {})
         AbstractObject.new(model.new(params))
@@ -56,8 +56,8 @@ def associations
       def properties
         columns = model.columns.reject do |c|
           c.type.blank? ||
-          DISABLED_COLUMN_TYPES.include?(c.type.to_sym) ||
-          c.try(:array)
+            DISABLED_COLUMN_TYPES.include?(c.type.to_sym) ||
+            c.try(:array)
         end
         columns.collect do |property|
           Property.new(property, model)
@@ -99,11 +99,12 @@ def initialize(scope)
 
         def add(field, value, operator)
           field.searchable_columns.flatten.each do |column_infos|
-            if value.is_a?(Array)
-              value = value.map { |v| field.parse_value(v) }
-            else
-              value = field.parse_value(value)
-            end
+            value =
+              if value.is_a?(Array)
+                value.map { |v| field.parse_value(v) }
+              else
+                field.parse_value(value)
+              end
             statement, value1, value2 = StatementBuilder.new(column_infos[:column], column_infos[:type], value, operator).to_statement
             @statements << statement if statement.present?
             @values << value1 unless value1.nil?
@@ -115,7 +116,7 @@ def add(field, value, operator)
 
         def build
           scope = @scope.where(@statements.join(' OR '), *@values)
-          scope = scope.references(*(@tables.uniq)) if @tables.any?
+          scope = scope.references(*@tables.uniq) if @tables.any?
           scope
         end
       end
@@ -211,7 +212,7 @@ def build_statement_for_string_or_text
             when 'ends_with'
               "%#{@value.downcase}"
             when 'is', '='
-              "#{@value.downcase}"
+              @value.downcase
             else
               return
             end
diff --git a/lib/rails_admin/adapters/mongoid.rb b/lib/rails_admin/adapters/mongoid.rb
index dee9147360..1c0a184364 100644
--- a/lib/rails_admin/adapters/mongoid.rb
+++ b/lib/rails_admin/adapters/mongoid.rb
@@ -8,7 +8,7 @@
 module RailsAdmin
   module Adapters
     module Mongoid
-      DISABLED_COLUMN_TYPES = %w(Range Moped::BSON::Binary BSON::Binary Mongoid::Geospatial::Point)
+      DISABLED_COLUMN_TYPES = %w(Range Moped::BSON::Binary BSON::Binary Mongoid::Geospatial::Point).freeze
 
       def parse_object_id(value)
         Bson.parse_object_id(value)
@@ -190,7 +190,7 @@ def sort_by(options, scope)
         when String
           field_name, collection_name = options[:sort].split('.').reverse
           if collection_name && collection_name != table_name
-            fail('sorting by associated model column is not supported in Non-Relational databases')
+            raise('sorting by associated model column is not supported in Non-Relational databases')
           end
         when Symbol
           field_name = options[:sort].to_s
diff --git a/lib/rails_admin/adapters/mongoid/association.rb b/lib/rails_admin/adapters/mongoid/association.rb
index 8ae7532d9a..b74ab6eb2a 100644
--- a/lib/rails_admin/adapters/mongoid/association.rb
+++ b/lib/rails_admin/adapters/mongoid/association.rb
@@ -28,7 +28,7 @@ def type
           when :has_and_belongs_to_many, :references_and_referenced_in_many
             :has_and_belongs_to_many
           else
-            fail("Unknown association type: #{macro.inspect}")
+            raise("Unknown association type: #{macro.inspect}")
           end
         end
 
@@ -83,7 +83,7 @@ def read_only?
         def nested_options
           nested = nested_attributes_options.try { |o| o[name] }
           if !nested && [:embeds_one, :embeds_many].include?(macro.to_sym) && !association.cyclic
-            fail <<-MSG.gsub(/^\s+/, '')
+            raise <<-MSG.gsub(/^\s+/, '')
             Embbeded association without accepts_nested_attributes_for can't be handled by RailsAdmin,
             because embedded model doesn't have top-level access.
             Please add `accepts_nested_attributes_for :#{association.name}' line to `#{model}' model.
diff --git a/lib/rails_admin/adapters/mongoid/extension.rb b/lib/rails_admin/adapters/mongoid/extension.rb
index 6258e3dff0..6c130fe5cd 100644
--- a/lib/rails_admin/adapters/mongoid/extension.rb
+++ b/lib/rails_admin/adapters/mongoid/extension.rb
@@ -16,7 +16,7 @@ def rails_admin(&block)
         end
 
         def rails_admin_default_object_label_method
-          self.new_record? ? "new #{self.class}" : "#{self.class} ##{id}"
+          new_record? ? "new #{self.class}" : "#{self.class} ##{id}"
         end
 
         def safe_send(value)
diff --git a/lib/rails_admin/adapters/mongoid/property.rb b/lib/rails_admin/adapters/mongoid/property.rb
index ffe0bb4130..fadf7bbe47 100644
--- a/lib/rails_admin/adapters/mongoid/property.rb
+++ b/lib/rails_admin/adapters/mongoid/property.rb
@@ -2,7 +2,7 @@ module RailsAdmin
   module Adapters
     module Mongoid
       class Property
-        STRING_TYPE_COLUMN_NAMES = [:name, :title, :subject]
+        STRING_TYPE_COLUMN_NAMES = [:name, :title, :subject].freeze
         attr_reader :property, :model
 
         def initialize(property, model)
diff --git a/lib/rails_admin/bootstrap-sass.rb b/lib/rails_admin/bootstrap-sass.rb
index 3aa90d9070..77a3980463 100755
--- a/lib/rails_admin/bootstrap-sass.rb
+++ b/lib/rails_admin/bootstrap-sass.rb
@@ -14,15 +14,13 @@ def self.load!
       require 'sass-rails' if rails?
 
       unless rails? || compass?
-        fail(Bootstrap::FrameworkNotFound.new('bootstrap-sass requires either Rails > 3.1 or Compass, neither of which are loaded'))
+        raise(Bootstrap::FrameworkNotFound.new('bootstrap-sass requires either Rails > 3.1 or Compass, neither of which are loaded'))
       end
 
       stylesheets = File.expand_path(File.join('..', 'vendor', 'assets', 'stylesheets'))
       ::Sass.load_paths << stylesheets
     end
 
-  private
-
     def self.asset_pipeline?
       defined?(::Sprockets)
     end
diff --git a/lib/rails_admin/bootstrap-sass/compass_functions.rb b/lib/rails_admin/bootstrap-sass/compass_functions.rb
index 91a55109f5..3e5ff870fa 100755
--- a/lib/rails_admin/bootstrap-sass/compass_functions.rb
+++ b/lib/rails_admin/bootstrap-sass/compass_functions.rb
@@ -8,7 +8,7 @@ def image_path(source, _options = {})
           image_url(source, Sass::Script::Bool.new(true))
         else
           # Revert to the old compass-agnostic path determination
-          asset_sans_quotes = source.value.gsub('"', '')
+          asset_sans_quotes = source.value.delete('"')
           Sass::Script::String.new("/images/#{asset_sans_quotes}", :string)
         end
       end
diff --git a/lib/rails_admin/config.rb b/lib/rails_admin/config.rb
index c1dde25fa3..37676b72dc 100644
--- a/lib/rails_admin/config.rb
+++ b/lib/rails_admin/config.rb
@@ -113,8 +113,8 @@ def audit_with(*args, &block)
           @audit = proc do
             @auditing_adapter = RailsAdmin::AUDITING_ADAPTERS[extension].new(*([self] + args).compact)
           end
-        else
-          @audit = block if block
+        elsif block
+          @audit = block
         end
         @audit || DEFAULT_AUDIT
       end
@@ -148,8 +148,8 @@ def authorize_with(*args, &block)
           @authorize = proc do
             @authorization_adapter = RailsAdmin::AUTHORIZATION_ADAPTERS[extension].new(*([self] + args).compact)
           end
-        else
-          @authorize = block if block
+        elsif block
+          @authorize = block
         end
         @authorize || DEFAULT_AUTHORIZE
       end
@@ -193,7 +193,7 @@ def default_search_operator=(operator)
         if %w(default like starts_with ends_with is =).include? operator
           @default_search_operator = operator
         else
-          fail(ArgumentError.new("Search operator '#{operator}' not supported"))
+          raise(ArgumentError.new("Search operator '#{operator}' not supported"))
         end
       end
 
diff --git a/lib/rails_admin/config/actions.rb b/lib/rails_admin/config/actions.rb
index c4a77822ac..6c4f33d49a 100644
--- a/lib/rails_admin/config/actions.rb
+++ b/lib/rails_admin/config/actions.rb
@@ -96,7 +96,7 @@ def add_action_custom_key(action, &block)
           action.instance_eval(&block) if block
           @@actions ||= []
           if action.custom_key.in?(@@actions.collect(&:custom_key))
-            fail "Action #{action.custom_key} already exists. Please change its custom key."
+            raise "Action #{action.custom_key} already exists. Please change its custom key."
           else
             @@actions << action
           end
diff --git a/lib/rails_admin/config/actions/base.rb b/lib/rails_admin/config/actions/base.rb
index 96e5e9db18..3dc5fb635e 100644
--- a/lib/rails_admin/config/actions/base.rb
+++ b/lib/rails_admin/config/actions/base.rb
@@ -115,12 +115,11 @@ class Base
 
         # Breadcrumb parent
         register_instance_option :breadcrumb_parent do
-          case
-          when root?
+          if root?
             [:dashboard]
-          when collection?
+          elsif collection?
             [:index, bindings[:abstract_model]]
-          when member?
+          elsif member?
             [:show, bindings[:abstract_model], bindings[:object]]
           end
         end
diff --git a/lib/rails_admin/config/actions/bulk_delete.rb b/lib/rails_admin/config/actions/bulk_delete.rb
index 2d05b42db7..a2aa821272 100644
--- a/lib/rails_admin/config/actions/bulk_delete.rb
+++ b/lib/rails_admin/config/actions/bulk_delete.rb
@@ -43,13 +43,11 @@ class BulkDelete < RailsAdmin::Config::Actions::Base
 
               if destroyed.nil?
                 flash[:error] = t('admin.flash.error', name: pluralize(0, @model_config.label), action: t('admin.actions.delete.done'))
-                redirect_to back_or_index
               else
                 flash[:success] = t('admin.flash.successful', name: pluralize(destroyed.count, @model_config.label), action: t('admin.actions.delete.done')) unless destroyed.empty?
                 flash[:error] = t('admin.flash.error', name: pluralize(not_destroyed.count, @model_config.label), action: t('admin.actions.delete.done')) unless not_destroyed.empty?
-                redirect_to back_or_index
               end
-
+              redirect_to back_or_index
             end
           end
         end
diff --git a/lib/rails_admin/config/actions/index.rb b/lib/rails_admin/config/actions/index.rb
index 757ec13ab3..ed72392e21 100644
--- a/lib/rails_admin/config/actions/index.rb
+++ b/lib/rails_admin/config/actions/index.rb
@@ -76,12 +76,10 @@ class Index < RailsAdmin::Config::Actions::Base
                   send_data output,
                             type: "text/csv; charset=#{encoding}; #{'header=present' if header}",
                             disposition: "attachment; filename=#{params[:model_name]}_#{DateTime.now.strftime('%Y-%m-%d_%Hh%Mm%S')}.csv"
+                elsif Rails.version.to_s >= '5'
+                  render plain: output
                 else
-                  if Rails.version.to_s >= '5'
-                    render plain: output
-                  else
-                    render text: output
-                  end
+                  render text: output
                 end
               end
             end
diff --git a/lib/rails_admin/config/configurable.rb b/lib/rails_admin/config/configurable.rb
index 2d5f06ac11..6bc9a93306 100644
--- a/lib/rails_admin/config/configurable.rb
+++ b/lib/rails_admin/config/configurable.rb
@@ -43,7 +43,7 @@ def register_instance_option(option_name, scope = self, &default)
 
           # Define getter/setter by the option name
           scope.send(:define_method, option_name) do |*args, &block|
-            if !args[0].nil? || block # rubocop:disable NonNilCheck
+            if !args[0].nil? || block
               # Invocation with args --> This is the declaration of the option, i.e. setter
               instance_variable_set("@#{option_name}_registered", args[0].nil? ? block : args[0])
             else
@@ -75,12 +75,10 @@ def register_deprecated_instance_option(option_name, replacement_option_name = n
             if replacement_option_name
               ActiveSupport::Deprecation.warn("The #{option_name} configuration option is deprecated, please use #{replacement_option_name}.")
               send(replacement_option_name, *args, &block)
+            elsif block_given?
+              yield
             else
-              if block_given?
-                yield
-              else
-                fail("The #{option_name} configuration option is removed without replacement.")
-              end
+              raise("The #{option_name} configuration option is removed without replacement.")
             end
           end
         end
diff --git a/lib/rails_admin/config/fields/association.rb b/lib/rails_admin/config/fields/association.rb
index a561cf54e4..20d0884ac5 100644
--- a/lib/rails_admin/config/fields/association.rb
+++ b/lib/rails_admin/config/fields/association.rb
@@ -10,7 +10,7 @@ def self.inherited(klass)
         end
 
         # Reader for the association information hash
-        def association # rubocop:disable TrivialAccessors
+        def association
           @properties
         end
 
diff --git a/lib/rails_admin/config/fields/base.rb b/lib/rails_admin/config/fields/base.rb
index b915c70498..2b3c2798a7 100644
--- a/lib/rails_admin/config/fields/base.rb
+++ b/lib/rails_admin/config/fields/base.rb
@@ -2,6 +2,7 @@
 require 'rails_admin/config/configurable'
 require 'rails_admin/config/hideable'
 require 'rails_admin/config/groupable'
+require 'rails_admin/config/inspectable'
 
 module RailsAdmin
   module Config
@@ -11,11 +12,17 @@ class Base # rubocop:disable ClassLength
         include RailsAdmin::Config::Configurable
         include RailsAdmin::Config::Hideable
         include RailsAdmin::Config::Groupable
+        include RailsAdmin::Config::Inspectable
 
         attr_reader :name, :properties, :abstract_model
         attr_accessor :defined, :order, :section
         attr_reader :parent, :root
 
+        NAMED_INSTANCE_VARIABLES = [
+          :@parent, :@root, :@section, :@children_fields_registered,
+          :@associated_model_config, :@group, :@bindings
+        ].freeze
+
         def initialize(parent, name, properties)
           @parent = parent
           @root = parent.root
@@ -57,7 +64,7 @@ def virtual?
         end
 
         register_instance_option :filterable? do
-          !!searchable # rubocop:disable DoubleNegation
+          !!searchable
         end
 
         register_instance_option :search_operator do
@@ -92,7 +99,7 @@ def virtual?
                   property = am && am.properties.detect { |p| p.name == f.values.first.to_sym }
                   type = property && property.type
                 else                                                             #  <attribute|column>
-                  am = (self.association? ? associated_model_config.abstract_model : abstract_model)
+                  am = (association? ? associated_model_config.abstract_model : abstract_model)
                   table_name = am.table_name
                   column = f
                   property = am.properties.detect { |p| p.name == f.to_sym }
@@ -172,12 +179,12 @@ def virtual?
               :nil
             end
           end
-          (@required ||= {})[context] ||= !!([name] + children_fields).uniq.detect do |column_name| # rubocop:disable DoubleNegation
+          (@required ||= {})[context] ||= !!([name] + children_fields).uniq.detect do |column_name|
             abstract_model.model.validators_on(column_name).detect do |v|
               !(v.options[:allow_nil] || v.options[:allow_blank]) &&
-              [:presence, :numericality, :attachment_presence].include?(v.kind) &&
-              (v.options[:on] == context || v.options[:on].blank?) &&
-              (v.options[:if].blank? && v.options[:unless].blank?)
+                [:presence, :numericality, :attachment_presence].include?(v.kind) &&
+                (v.options[:on] == context || v.options[:on].blank?) &&
+                (v.options[:if].blank? && v.options[:unless].blank?)
             end
           end
         end
@@ -247,8 +254,8 @@ def optional?
         #
         # @see RailsAdmin::Config::Fields::Base.register_instance_option :required?
         def optional(state = nil, &block)
-          if !state.nil? || block # rubocop:disable NonNilCheck
-            required state.nil? ? proc { false == (instance_eval(&block)) } : false == state
+          if !state.nil? || block
+            required state.nil? ? proc { false == instance_eval(&block) } : false == state
           else
             optional?
           end
@@ -324,24 +331,6 @@ def form_default_value
         def form_value
           form_default_value.nil? ? formatted_value : form_default_value
         end
-
-        def inspect
-          "#<#{self.class.name}[#{name}] #{
-            instance_variables.collect do |v|
-              value = instance_variable_get(v)
-              if [:@parent, :@root, :@section, :@children_fields_registered,
-                  :@associated_model_config, :@group, :@bindings].include? v
-                if value.respond_to? :name
-                  "#{v}=#{value.name.inspect}"
-                else
-                  "#{v}=#{value.class.name}"
-                end
-              else
-                "#{v}=#{value.inspect}"
-              end
-            end.join(', ')
-          }>"
-        end
       end
     end
   end
diff --git a/lib/rails_admin/config/fields/factories/carrierwave.rb b/lib/rails_admin/config/fields/factories/carrierwave.rb
index 7b1c1614b6..8491ae7f03 100644
--- a/lib/rails_admin/config/fields/factories/carrierwave.rb
+++ b/lib/rails_admin/config/fields/factories/carrierwave.rb
@@ -4,7 +4,7 @@
 
 RailsAdmin::Config::Fields.register_factory do |parent, properties, fields|
   model = parent.abstract_model.model
-  if defined?(::CarrierWave) && (model).is_a?(CarrierWave::Mount) && model.uploaders.include?(attachment_name = properties.name.to_s.chomp('_file_name').to_sym)
+  if defined?(::CarrierWave) && model.is_a?(CarrierWave::Mount) && model.uploaders.include?(attachment_name = properties.name.to_s.chomp('_file_name').to_sym)
     columns = [model.uploader_options[attachment_name][:mount_on] || attachment_name, "#{attachment_name}_content_type".to_sym, "#{attachment_name}_file_size".to_sym]
     field = RailsAdmin::Config::Fields::Types.load(:carrierwave).new(parent, attachment_name, properties)
     fields << field
diff --git a/lib/rails_admin/config/fields/types.rb b/lib/rails_admin/config/fields/types.rb
index 745506591e..03c3aa8633 100644
--- a/lib/rails_admin/config/fields/types.rb
+++ b/lib/rails_admin/config/fields/types.rb
@@ -9,7 +9,7 @@ module Types
         @@registry = {}
 
         def self.load(type)
-          @@registry[type.to_sym] || fail("Unsupported field datatype: #{type}")
+          @@registry[type.to_sym] || raise("Unsupported field datatype: #{type}")
         end
 
         def self.register(type, klass = nil)
diff --git a/lib/rails_admin/config/fields/types/file_upload.rb b/lib/rails_admin/config/fields/types/file_upload.rb
index 5f9f5b0b3f..3a01e2b389 100644
--- a/lib/rails_admin/config/fields/types/file_upload.rb
+++ b/lib/rails_admin/config/fields/types/file_upload.rb
@@ -57,7 +57,7 @@ class FileUpload < RailsAdmin::Config::Fields::Base
 
           # virtual class
           def resource_url
-            fail('not implemented')
+            raise('not implemented')
           end
 
           def virtual?
diff --git a/lib/rails_admin/config/fields/types/has_many_association.rb b/lib/rails_admin/config/fields/types/has_many_association.rb
index 2c62c4d5e9..c89386f86b 100644
--- a/lib/rails_admin/config/fields/types/has_many_association.rb
+++ b/lib/rails_admin/config/fields/types/has_many_association.rb
@@ -22,7 +22,7 @@ class HasManyAssociation < RailsAdmin::Config::Fields::Association
           end
 
           def method_name
-            nested_form ? "#{super}_attributes".to_sym : "#{super.to_s.singularize}_ids".to_sym  # name_ids
+            nested_form ? "#{super}_attributes".to_sym : "#{super.to_s.singularize}_ids".to_sym # name_ids
           end
 
           # Reader for validation errors of the bound object
diff --git a/lib/rails_admin/config/fields/types/polymorphic_association.rb b/lib/rails_admin/config/fields/types/polymorphic_association.rb
index 9e68004ae3..101c8bc3dc 100644
--- a/lib/rails_admin/config/fields/types/polymorphic_association.rb
+++ b/lib/rails_admin/config/fields/types/polymorphic_association.rb
@@ -16,7 +16,7 @@ class PolymorphicAssociation < RailsAdmin::Config::Fields::Types::BelongsToAssoc
           # association checks that any of the child models are included in
           # configuration.
           register_instance_option :visible? do
-            associated_model_config.length > 0
+            associated_model_config.any?
           end
 
           register_instance_option :formatted_value do
diff --git a/lib/rails_admin/config/fields/types/string.rb b/lib/rails_admin/config/fields/types/string.rb
index 07c3deb68b..ee2a6082cc 100644
--- a/lib/rails_admin/config/fields/types/string.rb
+++ b/lib/rails_admin/config/fields/types/string.rb
@@ -27,11 +27,12 @@ def generic_help
               max_length = [length, valid_length[:maximum] || nil].compact.min
               min_length = [0, valid_length[:minimum] || nil].compact.max
               if max_length
-                if min_length == 0
-                  text += "#{I18n.translate('admin.form.char_length_up_to').capitalize} #{max_length}."
-                else
-                  text += "#{I18n.translate('admin.form.char_length_of').capitalize} #{min_length}-#{max_length}."
-                end
+                text +=
+                  if min_length == 0
+                    "#{I18n.translate('admin.form.char_length_up_to').capitalize} #{max_length}."
+                  else
+                    "#{I18n.translate('admin.form.char_length_of').capitalize} #{min_length}-#{max_length}."
+                  end
               end
             end
             text
diff --git a/lib/rails_admin/config/fields/types/text.rb b/lib/rails_admin/config/fields/types/text.rb
index b4eb4ece32..e9c7948132 100644
--- a/lib/rails_admin/config/fields/types/text.rb
+++ b/lib/rails_admin/config/fields/types/text.rb
@@ -10,19 +10,19 @@ class Text < RailsAdmin::Config::Fields::Base
 
           [:ckeditor, :ckeditor_base_location, :ckeditor_config_js, :ckeditor_location].each do |key|
             register_deprecated_instance_option key do
-              fail("The 'field(:foo){ ckeditor true }' style DSL is deprecated. Please use 'field :foo, :ck_editor' instead.")
+              raise("The 'field(:foo){ ckeditor true }' style DSL is deprecated. Please use 'field :foo, :ck_editor' instead.")
             end
           end
 
           [:codemirror, :codemirror_assets, :codemirror_config, :codemirror_css_location, :codemirror_js_location].each do |key|
             register_deprecated_instance_option key do
-              fail("The 'field(:foo){ codemirror true }' style DSL is deprecated. Please use 'field :foo, :code_mirror' instead.")
+              raise("The 'field(:foo){ codemirror true }' style DSL is deprecated. Please use 'field :foo, :code_mirror' instead.")
             end
           end
 
           [:bootstrap_wysihtml5, :bootstrap_wysihtml5_config_options, :bootstrap_wysihtml5_css_location, :bootstrap_wysihtml5_js_location].each do |key|
             register_deprecated_instance_option key do
-              fail("The 'field(:foo){ bootstrap_wysihtml5 true }' style DSL is deprecated. Please use 'field :foo, :wysihtml5' instead.")
+              raise("The 'field(:foo){ bootstrap_wysihtml5 true }' style DSL is deprecated. Please use 'field :foo, :wysihtml5' instead.")
             end
           end
 
diff --git a/lib/rails_admin/config/hideable.rb b/lib/rails_admin/config/hideable.rb
index 85e889e671..8f8f699ca6 100644
--- a/lib/rails_admin/config/hideable.rb
+++ b/lib/rails_admin/config/hideable.rb
@@ -16,7 +16,7 @@ def hidden?
 
       # Writer to hide object.
       def hide(&block)
-        visible block ? proc { false == (instance_eval(&block)) } : false
+        visible block ? proc { false == instance_eval(&block) } : false
       end
 
       # Writer to show field.
diff --git a/lib/rails_admin/config/inspectable.rb b/lib/rails_admin/config/inspectable.rb
new file mode 100644
index 0000000000..e43ef5fd26
--- /dev/null
+++ b/lib/rails_admin/config/inspectable.rb
@@ -0,0 +1,39 @@
+module RailsAdmin
+  module Config
+    module Inspectable
+      def inspect
+        set_named_instance_variables
+
+        instance_name = try(:name) || try(:abstract_model).try(:model).try(:name)
+        instance_name = instance_name ? "[#{instance_name}]" : ''
+
+        instance_vars = instance_variables.collect do |v|
+          instance_variable_name(v)
+        end.join(', ')
+
+        "#<#{self.class.name}#{instance_name} #{instance_vars}>"
+      end
+
+    private
+
+      def instance_variable_name(variable)
+        value = instance_variable_get(variable)
+        if self.class::NAMED_INSTANCE_VARIABLES.include?(variable)
+          if value.respond_to?(:name)
+            "#{variable}=#{value.name.inspect}"
+          else
+            "#{variable}=#{value.class.name}"
+          end
+        else
+          "#{variable}=#{value.inspect}"
+        end
+      end
+
+      def set_named_instance_variables
+        unless defined?(self.class::NAMED_INSTANCE_VARIABLES)
+          self.class.const_set('NAMED_INSTANCE_VARIABLES', [])
+        end
+      end
+    end
+  end
+end
diff --git a/lib/rails_admin/config/model.rb b/lib/rails_admin/config/model.rb
index 71b6ff220f..8d679c7c2c 100644
--- a/lib/rails_admin/config/model.rb
+++ b/lib/rails_admin/config/model.rb
@@ -9,6 +9,7 @@
 require 'rails_admin/config/has_description'
 require 'rails_admin/config/sections'
 require 'rails_admin/config/actions'
+require 'rails_admin/config/inspectable'
 
 module RailsAdmin
   module Config
@@ -18,11 +19,14 @@ class Model
       include RailsAdmin::Config::Configurable
       include RailsAdmin::Config::Hideable
       include RailsAdmin::Config::Sections
+      include RailsAdmin::Config::Inspectable
 
       attr_reader :abstract_model
       attr_accessor :groups
       attr_reader :parent, :root
 
+      NAMED_INSTANCE_VARIABLES = [:@parent, :@root].freeze
+
       def initialize(entity)
         @parent = nil
         @root = self
@@ -98,23 +102,6 @@ def pluralize(count)
       def method_missing(m, *args, &block)
         send(:base).send(m, *args, &block)
       end
-
-      def inspect
-        "#<#{self.class.name}[#{abstract_model.model.name}] #{
-          instance_variables.collect do |v|
-            value = instance_variable_get(v)
-            if [:@parent, :@root].include? v
-              if value.respond_to? :name
-                "#{v}=#{value.name.inspect}"
-              else
-                "#{v}=#{value.class.name}"
-              end
-            else
-              "#{v}=#{value.inspect}"
-            end
-          end.join(', ')
-        }>"
-      end
     end
   end
 end
diff --git a/lib/rails_admin/config/sections/base.rb b/lib/rails_admin/config/sections/base.rb
index 1185dfbb1c..cdb8a5ffe1 100644
--- a/lib/rails_admin/config/sections/base.rb
+++ b/lib/rails_admin/config/sections/base.rb
@@ -1,5 +1,6 @@
 require 'rails_admin/config/proxyable'
 require 'rails_admin/config/configurable'
+require 'rails_admin/config/inspectable'
 require 'rails_admin/config/has_fields'
 require 'rails_admin/config/has_groups'
 require 'rails_admin/config/has_description'
@@ -11,6 +12,7 @@ module Sections
       class Base
         include RailsAdmin::Config::Proxyable
         include RailsAdmin::Config::Configurable
+        include RailsAdmin::Config::Inspectable
 
         include RailsAdmin::Config::HasFields
         include RailsAdmin::Config::HasGroups
@@ -19,29 +21,14 @@ class Base
         attr_reader :abstract_model
         attr_reader :parent, :root
 
+        NAMED_INSTANCE_VARIABLES = [:@parent, :@root, :@abstract_model].freeze
+
         def initialize(parent)
           @parent = parent
           @root = parent.root
 
           @abstract_model = root.abstract_model
         end
-
-        def inspect
-          "#<#{self.class.name} #{
-            instance_variables.collect do |v|
-              value = instance_variable_get(v)
-              if [:@parent, :@root, :@abstract_model].include? v
-                if value.respond_to? :name
-                  "#{v}=#{value.name.inspect}"
-                else
-                  "#{v}=#{value.class.name}"
-                end
-              else
-                "#{v}=#{value.inspect}"
-              end
-            end.join(', ')
-          }>"
-        end
       end
     end
   end
diff --git a/lib/rails_admin/engine.rb b/lib/rails_admin/engine.rb
index 8293ecbc94..245cb4bff5 100644
--- a/lib/rails_admin/engine.rb
+++ b/lib/rails_admin/engine.rb
@@ -12,7 +12,7 @@ module RailsAdmin
   class Engine < Rails::Engine
     isolate_namespace RailsAdmin
 
-    config.action_dispatch.rescue_responses.merge!('RailsAdmin::ActionNotAllowed' => :forbidden)
+    config.action_dispatch.rescue_responses['RailsAdmin::ActionNotAllowed'] = :forbidden
 
     initializer 'RailsAdmin precompile hook', group: :all do |app|
       app.config.assets.precompile += %w(
diff --git a/lib/rails_admin/extension.rb b/lib/rails_admin/extension.rb
index bc161d01a0..fd9738a77e 100644
--- a/lib/rails_admin/extension.rb
+++ b/lib/rails_admin/extension.rb
@@ -1,9 +1,9 @@
 
 module RailsAdmin
-  EXTENSIONS = []
-  AUTHORIZATION_ADAPTERS = {}
-  AUDITING_ADAPTERS = {}
-  CONFIGURATION_ADAPTERS = {}
+  EXTENSIONS = [] # rubocop:disable MutableConstant
+  AUTHORIZATION_ADAPTERS = {} # rubocop:disable MutableConstant
+  AUDITING_ADAPTERS = {} # rubocop:disable MutableConstant
+  CONFIGURATION_ADAPTERS = {} # rubocop:disable MutableConstant
 
   # Extend RailsAdmin
   #
diff --git a/lib/rails_admin/extensions/paper_trail/auditing_adapter.rb b/lib/rails_admin/extensions/paper_trail/auditing_adapter.rb
index 648ea986d9..94e6e51c54 100644
--- a/lib/rails_admin/extensions/paper_trail/auditing_adapter.rb
+++ b/lib/rails_admin/extensions/paper_trail/auditing_adapter.rb
@@ -36,10 +36,10 @@ class AuditingAdapter
           item: :item_id,
           created_at: :created_at,
           message: :event,
-        }
+        }.freeze
 
         def initialize(controller, user_class = 'User', version_class = '::Version')
-          fail('PaperTrail not found') unless defined?(PaperTrail)
+          raise('PaperTrail not found') unless defined?(PaperTrail)
           @controller = controller
           @controller.send(:set_paper_trail_whodunnit) if @controller
           begin
diff --git a/lib/rails_admin/extensions/pundit/authorization_adapter.rb b/lib/rails_admin/extensions/pundit/authorization_adapter.rb
index 3598c131d7..42355d3305 100644
--- a/lib/rails_admin/extensions/pundit/authorization_adapter.rb
+++ b/lib/rails_admin/extensions/pundit/authorization_adapter.rb
@@ -17,7 +17,9 @@ def initialize(controller)
         # instance if it is available.
         def authorize(action, abstract_model = nil, model_object = nil)
           record = model_object || abstract_model && abstract_model.model
-          fail ::Pundit::NotAuthorizedError.new("not allowed to #{action} this #{record}") unless policy(record).send(action_for_pundit(action)) if action
+          if action && !policy(record).send(action_for_pundit(action))
+            raise ::Pundit::NotAuthorizedError.new("not allowed to #{action} this #{record}")
+          end
         end
 
         # This method is called primarily from the view to determine whether the given user
diff --git a/lib/rails_admin/support/datetime.rb b/lib/rails_admin/support/datetime.rb
index 05b26c8a9c..e175c1b66c 100644
--- a/lib/rails_admin/support/datetime.rb
+++ b/lib/rails_admin/support/datetime.rb
@@ -23,7 +23,7 @@ class Datetime
         '%S' => 'ss',         # Second of the minute (00..60)
         '%Y' => 'YYYY',       # Year with century
         '%y' => 'YY',         # Year without a century (00..99)
-      }
+      }.freeze
 
       class << self
         include RailsAdmin::Support::I18n
diff --git a/lib/rails_admin/version.rb b/lib/rails_admin/version.rb
index 2f8f4dfebe..33cce2db8a 100644
--- a/lib/rails_admin/version.rb
+++ b/lib/rails_admin/version.rb
@@ -3,7 +3,7 @@ class Version
     MAJOR = 1
     MINOR = 0
     PATCH = 0
-    PRE = 'rc'
+    PRE = 'rc'.freeze
 
     class << self
       # @return [String]
diff --git a/spec/controllers/rails_admin/main_controller_spec.rb b/spec/controllers/rails_admin/main_controller_spec.rb
index e54ffdeb7e..fe2ef8e210 100644
--- a/spec/controllers/rails_admin/main_controller_spec.rb
+++ b/spec/controllers/rails_admin/main_controller_spec.rb
@@ -61,7 +61,7 @@ def get(action, params)
 
   describe '#check_for_cancel' do
     before do
-      allow(controller).to receive(:back_or_index) { fail(StandardError.new('redirected back')) }
+      allow(controller).to receive(:back_or_index) { raise(StandardError.new('redirected back')) }
     end
 
     it 'redirects to back if params[:bulk_ids] is nil when params[:bulk_action] is present' do
@@ -104,7 +104,7 @@ def get(action, params)
     end
 
     context 'using active_record, supporting joins', active_record: true do
-      it 'gives back the local column'  do
+      it 'gives back the local column' do
         controller.params = {sort: 'team', model_name: 'players'}
         expect(controller.send(:get_sort_hash, RailsAdmin.config(Player))).to eq(sort: 'teams.name', sort_reverse: true)
       end
@@ -113,7 +113,7 @@ def get(action, params)
 
   describe '#list_entries called from view' do
     before do
-      @teams = 21.times.collect { FactoryGirl.create :team }
+      @teams = FactoryGirl.create_list(:team, 21)
       controller.params = {model_name: 'teams'}
     end
 
@@ -125,7 +125,7 @@ def get(action, params)
 
   describe '#list_entries called from view with kaminari custom param_name' do
     before do
-      @teams = 21.times.collect { FactoryGirl.create :team }
+      @teams = FactoryGirl.create_list(:team, 21)
       controller.params = {model_name: 'teams'}
       Kaminari.config.param_name = :pagina
     end
@@ -142,7 +142,7 @@ def get(action, params)
 
   describe '#list_entries called with bulk_ids' do
     before do
-      @teams = 21.times.collect { FactoryGirl.create :team }
+      @teams = FactoryGirl.create_list(:team, 21)
       controller.params = {model_name: 'teams', bulk_action: 'bulk_delete', bulk_ids: @teams.collect(&:id)}
     end
 
@@ -159,9 +159,7 @@ def get(action, params)
     end
 
     it "doesn't scope associated collection records when associated_collection_scope is nil" do
-      @players = 2.times.collect do
-        FactoryGirl.create :player
-      end
+      @players = FactoryGirl.create_list(:player, 2)
 
       RailsAdmin.config Team do
         field :players do
@@ -173,9 +171,7 @@ def get(action, params)
     end
 
     it 'scopes associated collection records according to associated_collection_scope' do
-      @players = 4.times.collect do
-        FactoryGirl.create :player
-      end
+      @players = FactoryGirl.create_list(:player, 4)
 
       RailsAdmin.config Team do
         field :players do
@@ -192,9 +188,7 @@ def get(action, params)
       @team.revenue = BigDecimal.new('3')
       @team.save
 
-      @players = 5.times.collect do
-        FactoryGirl.create :player
-      end
+      @players = FactoryGirl.create_list(:player, 5)
 
       RailsAdmin.config Team do
         field :players do
@@ -211,9 +205,7 @@ def get(action, params)
     end
 
     it 'limits associated collection records number to 30 if cache_all is false' do
-      @players = 40.times.collect do
-        FactoryGirl.create :player
-      end
+      @players = FactoryGirl.create_list(:player, 40)
 
       RailsAdmin.config Team do
         field :players do
@@ -224,9 +216,7 @@ def get(action, params)
     end
 
     it "doesn't limit associated collection records number to 30 if cache_all is true" do
-      @players = 40.times.collect do
-        FactoryGirl.create :player
-      end
+      @players = FactoryGirl.create_list(:player, 40)
 
       RailsAdmin.config Team do
         field :players do
@@ -237,9 +227,7 @@ def get(action, params)
     end
 
     it 'orders associated collection records by id, descending' do
-      @players = 3.times.collect do
-        FactoryGirl.create :player
-      end
+      @players = FactoryGirl.create_list(:player, 3)
 
       expect(controller.list_entries.to_a).to eq(@players.sort_by(&:id).reverse)
     end
diff --git a/spec/dummy_app/app/active_record/ball.rb b/spec/dummy_app/app/active_record/ball.rb
index 69e2645e8a..fb6dd84010 100644
--- a/spec/dummy_app/app/active_record/ball.rb
+++ b/spec/dummy_app/app/active_record/ball.rb
@@ -2,6 +2,6 @@ class Ball < ActiveRecord::Base
   validates_presence_of :color, on: :create
 
   def to_param
-    color.present? ? color.downcase.gsub(' ', '-') : id
+    color.present? ? color.downcase.tr(' ', '-') : id
   end
 end
diff --git a/spec/dummy_app/app/mongoid/ball.rb b/spec/dummy_app/app/mongoid/ball.rb
index c64fc5bcc2..9b064d2e51 100644
--- a/spec/dummy_app/app/mongoid/ball.rb
+++ b/spec/dummy_app/app/mongoid/ball.rb
@@ -7,6 +7,6 @@ class Ball
   validates_presence_of :color, on: :create
 
   def to_param
-    color.present? ? color.downcase.gsub(' ', '-') : id
+    color.present? ? color.downcase.tr(' ', '-') : id
   end
 end
diff --git a/spec/dummy_app/config.ru b/spec/dummy_app/config.ru
index 5fb67aa8bd..7ae1c84900 100644
--- a/spec/dummy_app/config.ru
+++ b/spec/dummy_app/config.ru
@@ -1,4 +1,4 @@
 # This file is used by Rack-based servers to start the application.
 
-require ::File.expand_path('../config/environment',  __FILE__)
+require ::File.expand_path('../config/environment', __FILE__)
 run DummyApp::Application
diff --git a/spec/dummy_app/config/application.rb b/spec/dummy_app/config/application.rb
index 27d2163d71..30602e897c 100644
--- a/spec/dummy_app/config/application.rb
+++ b/spec/dummy_app/config/application.rb
@@ -5,7 +5,7 @@
 require 'sprockets/railtie'
 
 begin
-  require "#{CI_ORM}"
+  require CI_ORM.to_s
   require "#{CI_ORM}/railtie"
 rescue LoadError # rubocop:disable HandleExceptions
 end
diff --git a/spec/dummy_app/config/initializers/active_record_migration.rb b/spec/dummy_app/config/initializers/active_record_migration.rb
index f3b3a566c1..f74de6f242 100644
--- a/spec/dummy_app/config/initializers/active_record_migration.rb
+++ b/spec/dummy_app/config/initializers/active_record_migration.rb
@@ -1,7 +1,8 @@
 if defined?(ActiveRecord)
-  if Rails.version >= '5.0'
-    MigrationBase = ActiveRecord::Migration[5.0]
-  else
-    MigrationBase = ActiveRecord::Migration
-  end
+  MigrationBase = # rubocop:disable ConstantName
+    if Rails.version >= '5.0'
+      ActiveRecord::Migration[5.0]
+    else
+      ActiveRecord::Migration
+    end
 end
diff --git a/spec/dummy_app/db/migrate/00000000000012_add_avatar_columns_to_user.rb b/spec/dummy_app/db/migrate/00000000000012_add_avatar_columns_to_user.rb
index aceb50619e..f00090a655 100644
--- a/spec/dummy_app/db/migrate/00000000000012_add_avatar_columns_to_user.rb
+++ b/spec/dummy_app/db/migrate/00000000000012_add_avatar_columns_to_user.rb
@@ -1,15 +1,15 @@
-  class AddAvatarColumnsToUser < MigrationBase
-    def self.up
-      add_column :users, :avatar_file_name,    :string
-      add_column :users, :avatar_content_type, :string
-      add_column :users, :avatar_file_size,    :integer
-      add_column :users, :avatar_updated_at,   :datetime
-    end
+class AddAvatarColumnsToUser < MigrationBase
+  def self.up
+    add_column :users, :avatar_file_name,    :string
+    add_column :users, :avatar_content_type, :string
+    add_column :users, :avatar_file_size,    :integer
+    add_column :users, :avatar_updated_at,   :datetime
+  end
 
-    def self.down
-      remove_column :users, :avatar_file_name
-      remove_column :users, :avatar_content_type
-      remove_column :users, :avatar_file_size
-      remove_column :users, :avatar_updated_at
-    end
+  def self.down
+    remove_column :users, :avatar_file_name
+    remove_column :users, :avatar_content_type
+    remove_column :users, :avatar_file_size
+    remove_column :users, :avatar_updated_at
   end
+end
diff --git a/spec/dummy_app/db/migrate/00000000000013_add_roles_to_user.rb b/spec/dummy_app/db/migrate/00000000000013_add_roles_to_user.rb
index 9c32f1b5dd..60d4436f51 100644
--- a/spec/dummy_app/db/migrate/00000000000013_add_roles_to_user.rb
+++ b/spec/dummy_app/db/migrate/00000000000013_add_roles_to_user.rb
@@ -1,9 +1,9 @@
-  class AddRolesToUser < MigrationBase
-    def self.up
-      add_column :users, :roles, :string
-    end
+class AddRolesToUser < MigrationBase
+  def self.up
+    add_column :users, :roles, :string
+  end
 
-    def self.down
-      remove_column :users, :roles
-    end
+  def self.down
+    remove_column :users, :roles
   end
+end
diff --git a/spec/dummy_app/db/seeds.rb b/spec/dummy_app/db/seeds.rb
index 0152a19c9a..0c1834fa93 100644
--- a/spec/dummy_app/db/seeds.rb
+++ b/spec/dummy_app/db/seeds.rb
@@ -18,7 +18,7 @@
     division.save!
   end
   unless team = team_model.where(name: mlb_team.name).first
-    team = team_model.model.new(name: mlb_team.name, logo_url: mlb_team.logo_url, manager: mlb_team.manager || 'None', ballpark: mlb_team.ballpark, mascot: mlb_team.mascot, founded: mlb_team.founded, wins: mlb_team.wins, losses: mlb_team.losses, win_percentage: (format('%.3f', (mlb_team.wins.to_f / (mlb_team.wins + mlb_team.losses)))).to_f, division: division)
+    team = team_model.model.new(name: mlb_team.name, logo_url: mlb_team.logo_url, manager: mlb_team.manager || 'None', ballpark: mlb_team.ballpark, mascot: mlb_team.mascot, founded: mlb_team.founded, wins: mlb_team.wins, losses: mlb_team.losses, win_percentage: format('%.3f', (mlb_team.wins.to_f / (mlb_team.wins + mlb_team.losses))).to_f, division: division)
     team.save!
   end
   mlb_team.players.reject { |player| player.number.nil? }.each do |player|
diff --git a/spec/integration/basic/bulk_action/rails_admin_basic_bulk_action_spec.rb b/spec/integration/basic/bulk_action/rails_admin_basic_bulk_action_spec.rb
index 3670999462..78b0708c7d 100644
--- a/spec/integration/basic/bulk_action/rails_admin_basic_bulk_action_spec.rb
+++ b/spec/integration/basic/bulk_action/rails_admin_basic_bulk_action_spec.rb
@@ -4,7 +4,7 @@
   subject { page }
 
   before do
-    @players = 2.times.collect { FactoryGirl.create :player }
+    @players = FactoryGirl.create_list(:player, 2)
   end
 
   describe 'bulk_delete' do
diff --git a/spec/integration/basic/bulk_destroy/rails_admin_basic_bulk_destroy_spec.rb b/spec/integration/basic/bulk_destroy/rails_admin_basic_bulk_destroy_spec.rb
index 122698e8f4..12e369a8d6 100644
--- a/spec/integration/basic/bulk_destroy/rails_admin_basic_bulk_destroy_spec.rb
+++ b/spec/integration/basic/bulk_destroy/rails_admin_basic_bulk_destroy_spec.rb
@@ -7,7 +7,7 @@
     before do
       RailsAdmin::History.destroy_all
       RailsAdmin.config { |c| c.audit_with :history }
-      @players = 3.times.collect { FactoryGirl.create(:player) }
+      @players = Array.new(3) { FactoryGirl.create(:player) }
       @delete_ids = @players[0..1].collect(&:id)
 
       # NOTE: This uses an internal, unsupported capybara API which could break at any moment. We
@@ -34,7 +34,7 @@
 
   describe 'cancelled bulk_deletion' do
     before do
-      @players = 3.times.collect { FactoryGirl.create(:player) }
+      @players = Array.new(3) { FactoryGirl.create(:player) }
       @delete_ids = @players[0..1].collect(&:id)
 
       # NOTE: This uses an internal, unsupported capybara API which could break at any moment. We
diff --git a/spec/integration/basic/create/rails_admin_basic_create_spec.rb b/spec/integration/basic/create/rails_admin_basic_create_spec.rb
index 9e84b310fd..c9f09b774a 100644
--- a/spec/integration/basic/create/rails_admin_basic_create_spec.rb
+++ b/spec/integration/basic/create/rails_admin_basic_create_spec.rb
@@ -75,7 +75,7 @@
 
   describe 'create with has-many association' do
     before do
-      @divisions = 3.times.collect { Division.create!(name: "div #{Time.now.to_f}", league: League.create!(name: "league #{Time.now.to_f}")) }
+      @divisions = Array.new(3) { Division.create!(name: "div #{Time.now.to_f}", league: League.create!(name: "league #{Time.now.to_f}")) }
       post new_path(model_name: 'league', league: {name: 'National League', division_ids: [@divisions[0].id]})
       @league = RailsAdmin::AbstractModel.new('League').all.to_a.last
     end
@@ -90,7 +90,7 @@
 
   describe 'create with has-and-belongs-to-many association' do
     before do
-      @teams = 3.times.collect { FactoryGirl.create :team }
+      @teams = FactoryGirl.create_list(:team, 3)
       post new_path(model_name: 'fan', fan: {name: 'John Doe', team_ids: [@teams[0].id]})
       @fan = RailsAdmin::AbstractModel.new('Fan').first
     end
diff --git a/spec/integration/basic/edit/rails_admin_basic_edit_spec.rb b/spec/integration/basic/edit/rails_admin_basic_edit_spec.rb
index 023d187099..7362842300 100644
--- a/spec/integration/basic/edit/rails_admin_basic_edit_spec.rb
+++ b/spec/integration/basic/edit/rails_admin_basic_edit_spec.rb
@@ -68,7 +68,7 @@
 
   describe 'edit with has-and-belongs-to-many association' do
     before do
-      @teams = 3.times.collect { FactoryGirl.create :team }
+      @teams = FactoryGirl.create_list(:team, 3)
       @fan = FactoryGirl.create :fan, teams: [@teams[0]]
       visit edit_path(model_name: 'fan', id: @fan.id)
     end
@@ -95,7 +95,7 @@
   describe 'edit with missing label', given: ['a player exists', 'three teams with no name exist'] do
     before do
       @player = FactoryGirl.create :player
-      @teams = 3.times.collect { FactoryGirl.create :team, name: '' }
+      @teams = Array.new(3) { FactoryGirl.create :team, name: '' }
       visit edit_path(model_name: 'player', id: @player.id)
     end
   end
diff --git a/spec/integration/basic/export/rails_admin_basic_export_spec.rb b/spec/integration/basic/export/rails_admin_basic_export_spec.rb
index 8ce7f06f75..75765409f2 100644
--- a/spec/integration/basic/export/rails_admin_basic_export_spec.rb
+++ b/spec/integration/basic/export/rails_admin_basic_export_spec.rb
@@ -7,11 +7,11 @@
   before do
     Comment.all.collect(&:destroy) # rspec bug => doesn't get destroyed with transaction
 
-    @players = 4.times.collect { FactoryGirl.create :player }
+    @players = FactoryGirl.create_list(:player, 4)
     @player = @players.first
     @player.team = FactoryGirl.create :team
     @player.draft = FactoryGirl.create :draft
-    @player.comments = (@comments = 2.times.collect { FactoryGirl.create(:comment) })
+    @player.comments = (@comments = Array.new(2) { FactoryGirl.create(:comment) })
     @player.save
 
     @abstract_model = RailsAdmin::AbstractModel.new(Player)
diff --git a/spec/integration/basic/list/rails_admin_basic_list_spec.rb b/spec/integration/basic/list/rails_admin_basic_list_spec.rb
index 42d4e93686..2d5ab40dcd 100644
--- a/spec/integration/basic/list/rails_admin_basic_list_spec.rb
+++ b/spec/integration/basic/list/rails_admin_basic_list_spec.rb
@@ -55,7 +55,7 @@
 
   describe 'GET /admin/player' do
     before do
-      @teams = 2.times.collect do
+      @teams = Array.new(2) do
         FactoryGirl.create(:team)
       end
       @players = [
@@ -300,7 +300,7 @@
 
   describe 'GET /admin/player with 2 objects' do
     before do
-      @players = 2.times.collect { FactoryGirl.create :player }
+      @players = FactoryGirl.create_list(:player, 2)
       visit index_path(model_name: 'player')
     end
 
@@ -311,7 +311,7 @@
 
   describe 'GET /admin/player with 2 objects' do
     before do
-      @players = 2.times.collect { FactoryGirl.create :player }
+      @players = FactoryGirl.create_list(:player, 2)
       visit index_path(model_name: 'player')
     end
 
@@ -338,7 +338,7 @@
   describe 'list with 3 pages, page 3' do
     before do
       items_per_page = RailsAdmin.config.default_items_per_page
-      @players = (items_per_page * 3).times.collect { FactoryGirl.create(:player) }
+      @players = Array.new((items_per_page * 3)) { FactoryGirl.create(:player) }
       visit index_path(model_name: 'player', page: 3)
     end
 
@@ -358,7 +358,7 @@
     end
 
     it 'responds successfully with multiple models' do
-      2.times.collect { FactoryGirl.create :player }
+      FactoryGirl.create_list(:player, 2)
       visit index_path(model_name: 'player', all: true)
       expect(find('div.total-count')).to have_content('2 players')
     end
@@ -367,7 +367,7 @@
   describe 'GET /admin/player show with pagination disabled by :associated_collection' do
     it 'responds successfully' do
       @team = FactoryGirl.create :team
-      2.times.collect { FactoryGirl.create :player, team: @team }
+      Array.new(2) { FactoryGirl.create :player, team: @team }
       visit index_path(model_name: 'player', associated_collection: 'players', compact: true, current_action: 'update', source_abstract_model: 'team', source_object_id: @team.id)
       expect(find('div.total-count')).to have_content('2 players')
     end
@@ -375,7 +375,7 @@
 
   describe 'list as compact json' do
     it 'has_content an array with 2 elements and contain an array of elements with keys id and label' do
-      2.times.collect { FactoryGirl.create :player }
+      FactoryGirl.create_list(:player, 2)
       get index_path(model_name: 'player', compact: true, format: :json)
       expect(ActiveSupport::JSON.decode(response.body).length).to eq(2)
       ActiveSupport::JSON.decode(response.body).each do |object|
diff --git a/spec/integration/basic/update/rails_admin_basic_update_spec.rb b/spec/integration/basic/update/rails_admin_basic_update_spec.rb
index ae200ea5b3..eb1c8f3735 100644
--- a/spec/integration/basic/update/rails_admin_basic_update_spec.rb
+++ b/spec/integration/basic/update/rails_admin_basic_update_spec.rb
@@ -87,7 +87,7 @@
       end
 
       @league = FactoryGirl.create :league
-      @divisions = 3.times.collect { Division.create!(name: "div #{Time.now.to_f}", league: League.create!(name: "league #{Time.now.to_f}")) }
+      @divisions = Array.new(3) { Division.create!(name: "div #{Time.now.to_f}", league: League.create!(name: "league #{Time.now.to_f}")) }
 
       put edit_path(model_name: 'league', id: @league.id, league: {name: 'National League', division_ids: [@divisions[0].id]})
 
diff --git a/spec/integration/config/edit/rails_admin_config_edit_spec.rb b/spec/integration/config/edit/rails_admin_config_edit_spec.rb
index 708070e1ec..20665e2936 100644
--- a/spec/integration/config/edit/rails_admin_config_edit_spec.rb
+++ b/spec/integration/config/edit/rails_admin_config_edit_spec.rb
@@ -784,7 +784,8 @@ class HelpTest < Tableless
         expect(find('#field_test_nested_field_tests_attributes_0_title').value).to eq('nested title 1')
         is_expected.not_to have_selector('form .remove_nested_fields')
         expect(find('div#nested_field_tests_fields_blueprint', visible: false)[:'data-blueprint']).to match(
-          /<a[^>]* class="remove_nested_fields"[^>]*>/)
+          /<a[^>]* class="remove_nested_fields"[^>]*>/,
+        )
       end
     end
 
@@ -793,7 +794,8 @@ class HelpTest < Tableless
         visit new_path(model_name: 'field_test')
         is_expected.not_to have_selector('select#field_test_nested_field_tests_attributes_new_nested_field_tests_field_test_id')
         expect(find('div#nested_field_tests_fields_blueprint', visible: false)[:'data-blueprint']).to match(
-          /<select[^>]* id="field_test_nested_field_tests_attributes_new_nested_field_tests_another_field_test_id"[^>]*>/)
+          /<select[^>]* id="field_test_nested_field_tests_attributes_new_nested_field_tests_another_field_test_id"[^>]*>/,
+        )
       end
 
       it 'hides fields that are deeply nested with inverse_of' do
diff --git a/spec/integration/config/show/rails_admin_config_show_spec.rb b/spec/integration/config/show/rails_admin_config_show_spec.rb
index 9b9ca54ed5..6ed1a33a9f 100644
--- a/spec/integration/config/show/rails_admin_config_show_spec.rb
+++ b/spec/integration/config/show/rails_admin_config_show_spec.rb
@@ -88,9 +88,10 @@ def do_request
 
       is_expected.not_to have_selector('h4', text: 'Basic info')
 
-      %w(division name logo_url manager
-         ballpark mascot founded wins
-         losses win_percentage revenue
+      %w(
+        division name logo_url manager
+        ballpark mascot founded wins
+        losses win_percentage revenue
       ).each do |field|
         is_expected.not_to have_selector(".#{field}_field")
       end
@@ -186,9 +187,10 @@ def do_request
     it 'shows all by default' do
       do_request
 
-      %w(division name logo_url manager
-         ballpark mascot founded wins
-         losses win_percentage revenue players fans
+      %w(
+        division name logo_url manager
+        ballpark mascot founded wins
+        losses win_percentage revenue players fans
       ).each do |field|
         is_expected.to have_selector(".#{field}_field")
       end
@@ -253,9 +255,10 @@ def do_request
 
       do_request
 
-      ['Division', 'Name (STRING)', 'Logo url (STRING)', 'Manager (STRING)',
-       'Ballpark (STRING)', 'Mascot (STRING)', 'Founded', 'Wins', 'Losses',
-       'Win percentage', 'Revenue', 'Players', 'Fans'
+      [
+        'Division', 'Name (STRING)', 'Logo url (STRING)', 'Manager (STRING)',
+        'Ballpark (STRING)', 'Mascot (STRING)', 'Founded', 'Wins', 'Losses',
+        'Win percentage', 'Revenue', 'Players', 'Fans'
       ].each do |text|
         is_expected.to have_selector('.label', text: text)
       end
@@ -272,9 +275,10 @@ def do_request
 
       do_request
 
-      ['Division', 'Name (STRING)', 'Logo url (STRING)', 'Manager (STRING)',
-       'Ballpark (STRING)', 'Mascot (STRING)', 'Founded', 'Wins', 'Losses',
-       'Win percentage', 'Revenue', 'Players', 'Fans'
+      [
+        'Division', 'Name (STRING)', 'Logo url (STRING)', 'Manager (STRING)',
+        'Ballpark (STRING)', 'Mascot (STRING)', 'Founded', 'Wins', 'Losses',
+        'Win percentage', 'Revenue', 'Players', 'Fans'
       ].each do |text|
         is_expected.to have_selector('.label', text: text)
       end
diff --git a/spec/rails_admin/adapters/active_record_spec.rb b/spec/rails_admin/adapters/active_record_spec.rb
index 74d809d15b..05424bdeea 100644
--- a/spec/rails_admin/adapters/active_record_spec.rb
+++ b/spec/rails_admin/adapters/active_record_spec.rb
@@ -323,7 +323,7 @@ class PlayerWithDefaultScope < Player
 
     it 'supports datetime type query' do
       scope = FieldTest.all
-      expect(predicates_for(abstract_model.send(:filter_scope, scope,  'datetime_field' => {'1' => {v: ['', 'February 01, 2012 12:00', 'March 01, 2012 12:00'], o: 'between'}}))).to eq(predicates_for(scope.where(['(field_tests.datetime_field BETWEEN ? AND ?)', Time.local(2012, 2, 1), Time.local(2012, 3, 1).end_of_day])))
+      expect(predicates_for(abstract_model.send(:filter_scope, scope, 'datetime_field' => {'1' => {v: ['', 'February 01, 2012 12:00', 'March 01, 2012 12:00'], o: 'between'}}))).to eq(predicates_for(scope.where(['(field_tests.datetime_field BETWEEN ? AND ?)', Time.local(2012, 2, 1), Time.local(2012, 3, 1).end_of_day])))
       expect(predicates_for(abstract_model.send(:filter_scope, scope, 'datetime_field' => {'1' => {v: ['', 'March 01, 2012 12:00', ''], o: 'between'}}))).to eq(predicates_for(scope.where(['(field_tests.datetime_field >= ?)', Time.local(2012, 3, 1)])))
       expect(predicates_for(abstract_model.send(:filter_scope, scope, 'datetime_field' => {'1' => {v: ['', '', 'February 01, 2012 12:00'], o: 'between'}}))).to eq(predicates_for(scope.where(['(field_tests.datetime_field <= ?)', Time.local(2012, 2, 1).end_of_day])))
       expect(predicates_for(abstract_model.send(:filter_scope, scope, 'datetime_field' => {'1' => {v: ['February 01, 2012 12:00'], o: 'default'}}))).to eq(predicates_for(scope.where(['(field_tests.datetime_field BETWEEN ? AND ?)', Time.local(2012, 2, 1), Time.local(2012, 2, 1).end_of_day])))
diff --git a/spec/rails_admin/config/fields/base_spec.rb b/spec/rails_admin/config/fields/base_spec.rb
index 457df88b2a..b6eafc8b68 100644
--- a/spec/rails_admin/config/fields/base_spec.rb
+++ b/spec/rails_admin/config/fields/base_spec.rb
@@ -44,7 +44,7 @@ class ConditionalValidationTest < Tableless
   end
 
   describe '#children_fields' do
-    POLYMORPHIC_CHILDREN = [:commentable_id, :commentable_type]
+    POLYMORPHIC_CHILDREN = [:commentable_id, :commentable_type].freeze
 
     it 'is empty by default' do
       expect(RailsAdmin.config(Team).fields.detect { |f| f.name == :name }.children_fields).to eq([])
@@ -178,7 +178,7 @@ class CommentReversed < Tableless
     end
 
     it 'defaults to false if associated collection count >= 100' do
-      @players = 100.times.collect do
+      @players = Array.new(100) do
         FactoryGirl.create :player
       end
       expect(RailsAdmin.config(Team).edit.fields.detect { |f| f.name == :players }.associated_collection_cache_all).to be_falsey
@@ -189,14 +189,14 @@ class CommentReversed < Tableless
         RailsAdmin.config.default_associated_collection_limit = 5
       end
       it 'defaults to true if associated collection count less than than limit' do
-        @players = 4.times.collect do
+        @players = Array.new(4) do
           FactoryGirl.create :player
         end
         expect(RailsAdmin.config(Team).edit.fields.detect { |f| f.name == :players }.associated_collection_cache_all).to be_truthy
       end
 
       it 'defaults to false if associated collection count >= that limit' do
-        @players = 5.times.collect do
+        @players = Array.new(5) do
           FactoryGirl.create :player
         end
         expect(RailsAdmin.config(Team).edit.fields.detect { |f| f.name == :players }.associated_collection_cache_all).to be_falsey
diff --git a/spec/rails_admin/config_spec.rb b/spec/rails_admin/config_spec.rb
index b69ba01374..084d42c4dd 100644
--- a/spec/rails_admin/config_spec.rb
+++ b/spec/rails_admin/config_spec.rb
@@ -36,7 +36,7 @@
   describe '.add_extension' do
     before do
       silence_warnings do
-        RailsAdmin::EXTENSIONS = []
+        RailsAdmin::EXTENSIONS = [] # rubocop:disable MutableConstant
       end
     end
 
diff --git a/spec/rails_admin/support/csv_converter_spec.rb b/spec/rails_admin/support/csv_converter_spec.rb
index 379c8a2ffe..7c2a2a3e97 100644
--- a/spec/rails_admin/support/csv_converter_spec.rb
+++ b/spec/rails_admin/support/csv_converter_spec.rb
@@ -68,7 +68,7 @@
         expect(subject[1]).to eq 'UTF-8'
         expect(subject[2].encoding).to eq Encoding::UTF_8
         expect(subject[2].unpack('H*').first).
-          to eq 'efbbbf4e756d6265722c4e616d650a312ce381aae381bee381880a'  # have BOM
+          to eq 'efbbbf4e756d6265722c4e616d650a312ce381aae381bee381880a' # have BOM
       end
     end
 
diff --git a/spec/rails_admin/support/hash_helper_spec.rb b/spec/rails_admin/support/hash_helper_spec.rb
index f26fa5357f..bbe39cd990 100644
--- a/spec/rails_admin/support/hash_helper_spec.rb
+++ b/spec/rails_admin/support/hash_helper_spec.rb
@@ -4,12 +4,17 @@
 
 describe RailsAdmin::HashHelper do
   let(:hash) do
-    {'subject' => 'Test',
-     'user' => {name: 'Dirk',
-                'title' => 'Holistic Detective',
-                'clients' => [
-                  {name: 'Zaphod'},
-                  {'name' => 'Arthur'}]}}
+    {
+      'subject' => 'Test',
+      'user' => {
+        name: 'Dirk',
+        'title' => 'Holistic Detective',
+        'clients' => [
+          {name: 'Zaphod'},
+          {'name' => 'Arthur'},
+        ],
+      },
+    }
   end
 
   describe 'symbolize' do
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index dff660b621..013dd5b663 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,7 +1,7 @@
 # Configure Rails Envinronment
 ENV['RAILS_ENV'] = 'test'
 CI_ORM = (ENV['CI_ORM'] || :active_record).to_sym
-CI_TARGET_ORMS = [:active_record, :mongoid]
+CI_TARGET_ORMS = [:active_record, :mongoid].freeze
 PK_COLUMN = {active_record: :id, mongoid: :_id}[CI_ORM]
 
 require 'simplecov'