2 files changed, 5 insertions, 20 deletions
diff --git a/actionpack/lib/action_dispatch/testing/integration.rb b/actionpack/lib/action_dispatch/testing/integration.rb
index c6577d3d15..9a76b68ae1 100644
--- a/actionpack/lib/action_dispatch/testing/integration.rb
+++ b/actionpack/lib/action_dispatch/testing/integration.rb
@@ -717,7 +717,11 @@ module ActionDispatch
 
       module ClassMethods
         def app
-          @@app || ActionDispatch.test_app
+          if defined?(@@app) && @@app
+            @@app
+          else
+            ActionDispatch.test_app
+          end
         end
 
         def app=(app)
diff --git a/actionpack/test/controller/integration_test.rb b/actionpack/test/controller/integration_test.rb
index 5a711ae150..3b89531e90 100644
--- a/actionpack/test/controller/integration_test.rb
+++ b/actionpack/test/controller/integration_test.rb
@@ -397,25 +397,6 @@ class IntegrationTestUsesCorrectClass < ActionDispatch::IntegrationTest
   end
 end
 
-class IntegrationTestDefaultApp < ActionDispatch::IntegrationTest
-  def setup
-    @app = self.class.app
-    self.class.app = nil
-
-    @test_app = ActionDispatch.test_app
-    ActionDispatch.test_app = 'fake_app'
-  end
-
-  def teardown
-    self.class.app = @app
-    ActionDispatch.test_app = @test_app
-  end
-
-  def test_class_app_returns_ad_test_app_by_default
-    assert_equal 'fake_app', self.class.app
-  end
-end
-
 class IntegrationProcessTest < ActionDispatch::IntegrationTest
   class IntegrationController < ActionController::Base
     def get