Default connection allow_concurrency to false (for PostgreSQL)

Signed-off-by: Jeremy Kemper <jeremy@bitsweat.net>

activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb

@@ -164,8 +164,7 @@ module ActiveRecord
 
       private
       def new_connection
-        config = spec.config.reverse_merge(:allow_concurrency => true)
-        ActiveRecord::Base.send(spec.adapter_method, config)
+        ActiveRecord::Base.send(spec.adapter_method, spec.config)
       end
 
       def current_connection_id #:nodoc:

activerecord/lib/active_record/test_case.rb

@@ -43,5 +43,20 @@ module ActiveRecord
     def assert_no_queries(&block)
       assert_queries(0, &block)
     end
+
+    def self.use_concurrent_connections
+      setup :connection_allow_concurrency_setup
+      teardown :connection_allow_concurrency_teardown
+    end
+
+    def connection_allow_concurrency_setup
+      @connection = ActiveRecord::Base.remove_connection
+      ActiveRecord::Base.establish_connection(@connection.merge({:allow_concurrency => true}))
+    end
+
+    def connection_allow_concurrency_teardown
+      ActiveRecord::Base.clear_all_connections!
+      ActiveRecord::Base.establish_connection(@connection)
+    end
   end
 end

activerecord/test/cases/locking_test.rb

@@ -257,6 +257,8 @@ unless current_adapter?(:SQLServerAdapter, :SybaseAdapter, :OpenBaseAdapter)
     end
 
     if current_adapter?(:PostgreSQLAdapter, :OracleAdapter)
+      use_concurrent_connections
+
       def test_no_locks_no_wait
         first, second = duel { Person.find 1 }
         assert first.end > second.end

activerecord/test/cases/transactions_test.rb

@@ -284,6 +284,8 @@ end
 
 if current_adapter?(:PostgreSQLAdapter)
   class ConcurrentTransactionTest < TransactionTest
+    use_concurrent_connections
+
     # This will cause transactions to overlap and fail unless they are performed on
     # separate database connections.
     def test_transaction_per_thread