2 files changed, 39 insertions, 2 deletions
diff --git a/railties/test/application/middleware/show_exceptions_test.rb b/railties/test/application/middleware/show_exceptions_test.rb
new file mode 100644
index 0000000000..5487e41e0a
--- /dev/null
+++ b/railties/test/application/middleware/show_exceptions_test.rb
@@ -0,0 +1,37 @@
+require 'isolation/abstract_unit'
+
+module ApplicationTests
+  class ShowExceptionsTest < Test::Unit::TestCase
+    include ActiveSupport::Testing::Isolation
+
+    def setup
+      build_app
+      boot_rails
+      FileUtils.rm_rf "#{app_path}/config/environments"
+    end
+
+    def app
+      @app ||= Rails.application
+    end
+
+    test "unspecified route when set action_dispatch.show_exceptions to false" do
+      make_basic_app do |app|
+        app.config.action_dispatch.show_exceptions = false
+      end
+
+      assert_raise(ActionController::RoutingError) do
+        get '/foo'
+      end
+    end
+
+    test "unspecified route when set action_dispatch.show_exceptions to true" do
+      make_basic_app do |app|
+        app.config.action_dispatch.show_exceptions = true
+      end
+
+      assert_nothing_raised(ActionController::RoutingError) do
+        get '/foo'
+      end
+    end
+  end
+end
diff --git a/railties/test/application/middleware_test.rb b/railties/test/application/middleware_test.rb
index 44dd0bc8e4..b314832685 100644
--- a/railties/test/application/middleware_test.rb
+++ b/railties/test/application/middleware_test.rb
@@ -78,10 +78,10 @@ module ApplicationTests
       assert !middleware.include?("ActionDispatch::Static")
     end
 
-    test "removes show exceptions if action_dispatch.show_exceptions is disabled" do
+    test "includes show exceptions even action_dispatch.show_exceptions is disabled" do
       add_to_config "config.action_dispatch.show_exceptions = false"
       boot!
-      assert !middleware.include?("ActionDispatch::ShowExceptions")
+      assert middleware.include?("ActionDispatch::ShowExceptions")
     end
 
     test "removes ActionDispatch::Reloader if cache_classes is true" do