diff --git a/.rubocop.yml b/.rubocop.yml
index 6c393cf7e..184624970 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -111,6 +111,10 @@ Style/ClassVars:
     - 'spec/mongoid/clients/transactions_spec_models.rb'
     - 'spec/mongoid/contextual/mongo/documents_loader_spec.rb'
 
+Style/OpenStructUse:
+  Exclude:
+    - 'lib/mongoid/indexable.rb'
+
 Style/CaseEquality:
   Exclude:
     - 'lib/mongoid/association/embedded/embeds_many/proxy.rb'
diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 8d77ae1b0..c8ebd04c3 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -828,13 +828,6 @@ Style/MultilineBlockChain:
     - 'spec/mongoid/changeable_spec.rb'
     - 'spec/mongoid/document_spec.rb'
 
-# Offense count: 4
-Style/OpenStructUse:
-  Exclude:
-    - 'lib/mongoid/indexable.rb'
-    - 'spec/rails/controller_extension/controller_runtime_spec.rb'
-    - 'spec/support/rails_mock.rb'
-
 # Offense count: 17
 # Configuration parameters: AllowedMethods.
 # AllowedMethods: respond_to_missing?
diff --git a/spec/rails/controller_extension/controller_runtime_spec.rb b/spec/rails/controller_extension/controller_runtime_spec.rb
index c61435dfa..0244e60f2 100644
--- a/spec/rails/controller_extension/controller_runtime_spec.rb
+++ b/spec/rails/controller_extension/controller_runtime_spec.rb
@@ -41,6 +41,10 @@ def clear_metric!
 
   describe 'Collector' do
 
+    before do
+      stub_const('EventPayload', Struct.new(:duration))
+    end
+
     it 'stores the metric in thread-safe manner' do
       clear_metric!
       expect(collector.runtime).to eq(0)
@@ -50,7 +54,7 @@ def clear_metric!
 
     it 'sets metric on both succeeded and failed' do
       instance = collector.new
-      event_payload = OpenStruct.new duration: 42
+      event_payload = EventPayload.new(42)
 
       clear_metric!
       instance.succeeded event_payload
diff --git a/spec/support/rails_mock.rb b/spec/support/rails_mock.rb
index 7d4b1248b..9e65b583d 100644
--- a/spec/support/rails_mock.rb
+++ b/spec/support/rails_mock.rb
@@ -19,11 +19,15 @@ def eager_load!; end
   end
 end
 
+ConfigPaths = Struct.new(:expanded)
+
+AppConfig = Struct.new(:paths)
+
 Rails.env = 'development'
 Rails.root = Pathname.new('.')
 Rails.logger = Logger.new($stdout)
 Rails.application = Rails::Application
 
-Rails.application.config = OpenStruct.new(
-  paths: { 'app/models' => OpenStruct.new(expanded: ['app/models']) }
+Rails.application.config = AppConfig.new(
+  paths: { 'app/models' => ConfigPaths.new(['app/models']) }
 )