From 6da5186aaa90c44498c7c6978dbc23568269d0dc Mon Sep 17 00:00:00 2001
From: Santiago Pastorino <santiago@wyeworks.com>
Date: Tue, 26 Jul 2016 22:02:38 -0300
Subject: [PATCH] There are some cases where @@app is not defined

---
 .../action_dispatch/testing/integration.rb    |  6 +++-
 .../test/controller/integration_test.rb       | 19 -------------
 .../application/integration_test_case_test.rb | 28 +++++++++++++++++++
 3 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/actionpack/lib/action_dispatch/testing/integration.rb b/actionpack/lib/action_dispatch/testing/integration.rb
index 749163a327..9404a18699 100644
--- a/actionpack/lib/action_dispatch/testing/integration.rb
+++ b/actionpack/lib/action_dispatch/testing/integration.rb
@@ -712,7 +712,11 @@ 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 dc3665ed78..6a511e2f68 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
diff --git a/railties/test/application/integration_test_case_test.rb b/railties/test/application/integration_test_case_test.rb
index d106d5159a..b6e4f02055 100644
--- a/railties/test/application/integration_test_case_test.rb
+++ b/railties/test/application/integration_test_case_test.rb
@@ -43,4 +43,32 @@ module ApplicationTests
       assert_match(/0 failures, 0 errors/, output)
     end
   end
+
+  class IntegrationTestDefaultApp < ActiveSupport::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    setup do
+      build_app
+    end
+
+    teardown do
+      teardown_app
+    end
+
+    test "app method of integration tests returns test_app by default" do
+      app_file 'test/integration/default_app_test.rb', <<-RUBY
+        require 'test_helper'
+
+        class DefaultAppIntegrationTest < ActionDispatch::IntegrationTest
+          def test_app_returns_action_dispatch_test_app_by_default
+            assert_equal ActionDispatch.test_app, app
+          end
+        end
+      RUBY
+
+      output = Dir.chdir(app_path) { `bin/rails test 2>&1` }
+      assert_equal 0, $?.to_i, output
+      assert_match(/0 failures, 0 errors/, output)
+    end
+  end
 end