3 files changed, 8 insertions, 0 deletions
diff --git a/activemodel/Rakefile b/activemodel/Rakefile
index 4b60f8d682..544f49310a 100755
--- a/activemodel/Rakefile
+++ b/activemodel/Rakefile
@@ -11,6 +11,12 @@ Rake::TestTask.new do |t|
   t.verbose = true
   t.warning = true
 end
+task :isolated_test do
+  ruby = File.join(*RbConfig::CONFIG.values_at('bindir', 'RUBY_INSTALL_NAME'))
+  Dir.glob("test/**/*_test.rb").all? do |file|
+    system(ruby, '-Ilib:test', file)
+  end or raise "Failures"
+end
 
 # Generate the RDoc documentation
 Rake::RDocTask.new do |rdoc|
diff --git a/activemodel/test/state_machine/event_test.rb b/activemodel/test/state_machine/event_test.rb
index 64dc8c4875..05e7c78e8a 100644
--- a/activemodel/test/state_machine/event_test.rb
+++ b/activemodel/test/state_machine/event_test.rb
@@ -1,4 +1,5 @@
 require 'test_helper'
+require 'active_model/state_machine/event'
 
 class EventTest < ActiveModel::TestCase
   def setup
diff --git a/activemodel/test/state_machine/state_transition_test.rb b/activemodel/test/state_machine/state_transition_test.rb
index b59ff5a6a7..966396fab1 100644
--- a/activemodel/test/state_machine/state_transition_test.rb
+++ b/activemodel/test/state_machine/state_transition_test.rb
@@ -1,4 +1,5 @@
 require 'test_helper'
+require 'active_model/state_machine/state_transition'
 
 class StateTransitionTest < ActiveModel::TestCase
   test 'should set from, to, and opts attr readers' do