Also check config.allow_concurrency to match Rails 4.2 behavior for Rack::Lock

History.md

@@ -1,3 +1,9 @@
+# Version 2.4.3
+Relase date: 2014-09-21
+
+###Fixed
+* Update concurrency prevention to match Rails 4.2 behavior
+
 # Version 2.4.2
 Release date: 2014-09-20
 

lib/capybara/rails.rb

@@ -5,7 +5,7 @@ Capybara.app = Rack::Builder.new do
   # Work around an issue where rails allows concurrency in test mode even though eager_load
   # is false which can cause an issue with constant loading
   if Gem::Version.new(Rails.version) >= Gem::Version.new("4.0")
-    use Rack::Lock unless Rails.application.config.eager_load || Rails.application.middleware.include?(Rack::Lock)
+    use Rack::Lock unless Rails.application.config.allow_concurrency || Rails.application.config.eager_load || Rails.application.middleware.include?(Rack::Lock)
   end
   
   map "/" do