diff --git a/Appraisals b/Appraisals
index 3002ea39..5086c4d4 100644
--- a/Appraisals
+++ b/Appraisals
@@ -9,3 +9,8 @@ end
 appraise "rails-4.0" do
   gem 'rails', '~> 4.0'
 end
+
+appraise "rails-4.0-with-therubyracer" do
+  gem 'rails', '~> 4.0'
+  gem 'therubyracer', '0.12.0', :platform => :mri
+end
diff --git a/lib/react/jsx.rb b/lib/react/jsx.rb
index 767fc419..c9cfa24c 100644
--- a/lib/react/jsx.rb
+++ b/lib/react/jsx.rb
@@ -6,7 +6,11 @@ module React
   module JSX
     def self.context
       # TODO: create React::Source::contents_for
-      contents = File.read(React::Source.bundled_path_for('JSXTransformer.js'))
+      contents =
+        # If execjs uses therubyracer, there is no 'global'. Make sure
+        # we have it so JSX script can work properly.
+        'var global = global || this;' +
+        File.read(React::Source.bundled_path_for('JSXTransformer.js'))
       @context ||= ExecJS.compile(contents)
     end
 
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 1e26a313..c900e969 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -6,6 +6,12 @@
 
 Rails.backtrace_cleaner.remove_silencers!
 
+# Remove cached files
+Rails.root.join('tmp').tap do |tmp|
+  tmp.rmtree
+  tmp.mkpath
+end
+
 # Load support files
 Dir["#{File.dirname(__FILE__)}/support/**/*.rb"].each { |f| require f }