1 files changed, 31 insertions, 3 deletions
diff --git a/railties/test/application/integration_test_case_test.rb b/railties/test/application/integration_test_case_test.rb
index 52df5a2e5a..1118e5037a 100644
--- a/railties/test/application/integration_test_case_test.rb
+++ b/railties/test/application/integration_test_case_test.rb
@@ -1,4 +1,4 @@
-require 'isolation/abstract_unit'
+require "isolation/abstract_unit"
 
 module ApplicationTests
   class IntegrationTestCaseTest < ActiveSupport::TestCase
@@ -13,9 +13,9 @@ module ApplicationTests
     end
 
     test "resets Action Mailer test deliveries" do
-      script('generate mailer BaseMailer welcome')
+      script("generate mailer BaseMailer welcome")
 
-      app_file 'test/integration/mailer_integration_test.rb', <<-RUBY
+      app_file "test/integration/mailer_integration_test.rb", <<-RUBY
         require 'test_helper'
 
         class MailerIntegrationTest < ActionDispatch::IntegrationTest
@@ -42,4 +42,32 @@ 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