Skip isolation test tests when using MiniTest

activesupport/test/isolation_test.rb

@@ -1,7 +1,9 @@
 require 'abstract_unit'
 
 # Does awesome
-if ENV['CHILD']
+if defined?(MiniTest)
+  $stderr.puts "Umm, MiniTest not supported yet, mmkay?"
+elsif ENV['CHILD']
   class ChildIsolationTest < ActiveSupport::TestCase
     include ActiveSupport::Testing::Isolation
 
@@ -153,4 +155,4 @@ else
     end
 
   end
-end
+end