Override todo types for EE

Create a separate TodosFinder spec file for EE

Avoid creating additional Set instances

Change todo_types to class method

Updating specs as well

Move spec files to correct locations

Remove ee stub

Remove ee specs for TodosFinder
and refactor TodosFinder specs

Apply suggestion to
ee/app/finders/ee/todos_finder.rb

app/finders/todos_finder.rb

@@ -23,10 +23,16 @@ class TodosFinder
 
   NONE = '0'
 
-  TODO_TYPES = Set.new(%w(Issue MergeRequest Epic)).freeze
+  TODO_TYPES = Set.new(%w(Issue MergeRequest)).freeze
 
   attr_accessor :current_user, :params
 
+  class << self
+    def todo_types
+      TODO_TYPES
+    end
+  end
+
   def initialize(current_user, params = {})
     @current_user = current_user
     @params = params
@@ -124,7 +130,7 @@ class TodosFinder
   end
 
   def type?
-    type.present? && TODO_TYPES.include?(type)
+    type.present? && self.class.todo_types.include?(type)
   end
 
   def type
@@ -201,3 +207,5 @@ class TodosFinder
     end
   end
 end
+
+TodosFinder.prepend_if_ee('EE::TodosFinder')

ee/app/finders/ee/todos_finder.rb

+# frozen_string_literal: true
+
+module EE
+  module TodosFinder
+    extend ActiveSupport::Concern
+
+    EE_TODO_TYPES = (::TodosFinder::TODO_TYPES + %w[Epic]).freeze
+
+    class_methods do
+      extend ::Gitlab::Utils::Override
+
+      override :todo_types
+      def todo_types
+        EE_TODO_TYPES
+      end
+    end
+  end
+end

spec/finders/todos_finder_spec.rb

@@ -234,6 +234,19 @@ describe TodosFinder do
     end
   end
 
+  describe '.todo_types' do
+    it 'returns the expected types' do
+      expected_result =
+        if Gitlab.ee?
+          %w[Epic Issue MergeRequest]
+        else
+          %w[Issue MergeRequest]
+        end
+
+      expect(described_class.todo_types).to contain_exactly(*expected_result)
+    end
+  end
+
   describe '#any_for_target?' do
     it 'returns true if there are any todos for the given target' do
       todo = create(:todo, :pending)