Fix FactoryBot/FactoryClassName to ignore Hash and OpenStruct

Hash and OpenStruct are used in factories widely.
The factory should not force them into strings as they are
built in language objects.

Author: fragoulis

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Master (Unreleased)
 
 * Improve message and description of `FactoryBot/FactoryClassName`. ([@ybiquitous][])
+* Fix `FactoryBot/FactoryClassName` to ignore `Hash` and `OpenStruct`. ([@jfragoulis][])
 
 ## 1.37.0 (2019-11-25)
 

lib/rubocop/cop/rspec/factory_bot/factory_class_name.rb

@@ -22,13 +22,16 @@ module FactoryBot
         class FactoryClassName < Cop
           MSG = "Pass '%<class_name>s' string instead of `%<class_name>s` " \
                 'constant.'
+          ALLOWED_CONSTANTS = %w[Hash OpenStruct].freeze
 
           def_node_matcher :class_name, <<~PATTERN
             (send _ :factory _ (hash <(pair (sym :class) $(const ...)) ...>))
           PATTERN
 
           def on_send(node)
             class_name(node) do |cn|
+              next if allowed?(cn.const_name)
+
               add_offense(cn, message: format(MSG, class_name: cn.const_name))
             end
           end
@@ -38,6 +41,12 @@ def autocorrect(node)
               corrector.replace(node.loc.expression, "'#{node.source}'")
             end
           end
+
+          private
+
+          def allowed?(const_name)
+            ALLOWED_CONSTANTS.include?(const_name)
+          end
         end
       end
     end

spec/rubocop/cop/rspec/factory_bot/factory_class_name_spec.rb

@@ -49,6 +49,20 @@
         end
       RUBY
     end
+
+    it 'ignores passing Hash' do
+      expect_no_offenses(<<~RUBY)
+        factory :foo, class: Hash do
+        end
+      RUBY
+    end
+
+    it 'ignores passing OpenStruct' do
+      expect_no_offenses(<<~RUBY)
+        factory :foo, class: OpenStruct do
+        end
+      RUBY
+    end
   end
 
   context 'when not passing block' do