Enable hstore extensions on tests if it is not enabled and database supports it

activerecord/test/cases/adapters/postgresql/hstore_test.rb

@@ -11,11 +11,18 @@ class Hstore < ActiveRecord::Base
 
   def setup
     @connection = ActiveRecord::Base.connection
+
+    unless @connection.supports_extensions?
+      return skip "do not test on PG without hstore"
+    end
+
     unless @connection.extension_enabled?('hstore')
       @connection.enable_extension 'hstore'
-      return skip "do not test on PG without hstore"
+      @connection.commit_db_transaction
     end
 
+    @connection.reconnect!
+
     @connection.transaction do
       @connection.create_table('hstores') do |t|
         t.hstore 'tags', :default => ''