Add ConnectionHelper to refactor tests.

activerecord/test/cases/adapters/mysql/active_schema_test.rb

 require "cases/helper"
+require 'support/connection_helper'
 
 class ActiveSchemaTest < ActiveRecord::TestCase
-  def setup
-    @connection = ActiveRecord::Base.remove_connection
-    ActiveRecord::Base.establish_connection(@connection)
+  include ConnectionHelper
 
+  def setup
     ActiveRecord::Base.connection.singleton_class.class_eval do
       alias_method :execute_without_stub, :execute
       def execute(sql, name = nil) return sql end
@@ -12,8 +12,7 @@ def execute(sql, name = nil) return sql end
   end
 
   teardown do
-    ActiveRecord::Base.remove_connection
-    ActiveRecord::Base.establish_connection(@connection)
+    reset_connection
   end
 
   def test_add_index

activerecord/test/cases/adapters/mysql/connection_test.rb

 require "cases/helper"
+require 'support/connection_helper'
 require 'support/ddl_helper'
 
 class MysqlConnectionTest < ActiveRecord::TestCase
+  include ConnectionHelper
   include DdlHelper
 
   class Klass < ActiveRecord::Base
@@ -160,15 +162,6 @@ def test_mysql_set_session_variable_to_default
 
   private
 
-  def run_without_connection
-    original_connection = ActiveRecord::Base.remove_connection
-    begin
-      yield original_connection
-    ensure
-      ActiveRecord::Base.establish_connection(original_connection)
-    end
-  end
-
   def with_example_table(&block)
     definition ||= <<-SQL
       `id` int(11) auto_increment PRIMARY KEY,

activerecord/test/cases/adapters/mysql2/active_schema_test.rb

 require "cases/helper"
+require 'support/connection_helper'
 
 class ActiveSchemaTest < ActiveRecord::TestCase
-  def setup
-    @connection = ActiveRecord::Base.remove_connection
-    ActiveRecord::Base.establish_connection(@connection)
+  include ConnectionHelper
 
+  def setup
     ActiveRecord::Base.connection.singleton_class.class_eval do
       alias_method :execute_without_stub, :execute
       def execute(sql, name = nil) return sql end
@@ -12,8 +12,7 @@ def execute(sql, name = nil) return sql end
   end
 
   teardown do
-    ActiveRecord::Base.remove_connection
-    ActiveRecord::Base.establish_connection(@connection)
+    reset_connection
   end
 
   def test_add_index

activerecord/test/cases/adapters/mysql2/connection_test.rb

 require "cases/helper"
+require 'support/connection_helper'
 
 class MysqlConnectionTest < ActiveRecord::TestCase
+  include ConnectionHelper
+
   def setup
     super
     @subscriber = SQLSubscriber.new
@@ -103,15 +106,4 @@ def test_quote_time_usec
       assert_equal "'1970-01-01 00:00:00.000000'", @connection.quote(Time.at(0).to_datetime)
     end
   end
-
-  private
-
-  def run_without_connection
-    original_connection = ActiveRecord::Base.remove_connection
-    begin
-      yield original_connection
-    ensure
-      ActiveRecord::Base.establish_connection(original_connection)
-    end
-  end
 end

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

 require "cases/helper"
+require 'support/connection_helper'
 
 module ActiveRecord
   class PostgresqlConnectionTest < ActiveRecord::TestCase
+    include ConnectionHelper
+
     class NonExistentTable < ActiveRecord::Base
     end
 
@@ -198,17 +201,5 @@ def test_set_session_variable_default
         ActiveRecord::Base.establish_connection(orig_connection.deep_merge({:variables => {:debug_print_plan => :default}}))
       end
     end
-
-    private
-
-    def run_without_connection
-      original_connection = ActiveRecord::Base.remove_connection
-      begin
-        yield original_connection
-      ensure
-        ActiveRecord::Base.establish_connection(original_connection)
-      end
-    end
-
   end
 end

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

 # -*- coding: utf-8 -*-
 require "cases/helper"
-require 'support/postgresql_helper'
+require 'support/connection_helper'
 require 'active_record/base'
 require 'active_record/connection_adapters/postgresql_adapter'
 
 class PostgresqlDomainTest < ActiveRecord::TestCase
-  include PostgresqlHelper
+  include ConnectionHelper
 
   class PostgresqlDomain < ActiveRecord::Base
     self.table_name = "postgresql_domains"
@@ -27,7 +27,7 @@ def setup
   teardown do
     @connection.execute 'DROP TABLE IF EXISTS postgresql_domains'
     @connection.execute 'DROP DOMAIN IF EXISTS custom_money'
-    reset_pg_session
+    reset_connection
   end
 
   def test_column

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

 # -*- coding: utf-8 -*-
 require "cases/helper"
-require 'support/postgresql_helper'
+require 'support/connection_helper'
 require 'active_record/base'
 require 'active_record/connection_adapters/postgresql_adapter'
 
 class PostgresqlEnumTest < ActiveRecord::TestCase
-  include PostgresqlHelper
+  include ConnectionHelper
 
   class PostgresqlEnum < ActiveRecord::Base
     self.table_name = "postgresql_enums"
@@ -28,7 +28,7 @@ def setup
   teardown do
     @connection.execute 'DROP TABLE IF EXISTS postgresql_enums'
     @connection.execute 'DROP TYPE IF EXISTS mood'
-    reset_pg_session
+    reset_connection
   end
 
   def test_column

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

 require "cases/helper"
-require 'support/postgresql_helper'
+require 'support/connection_helper'
 require 'active_record/base'
 require 'active_record/connection_adapters/postgresql_adapter'
 
@@ -10,13 +10,7 @@ class PostgresqlRange < ActiveRecord::Base
 
   class PostgresqlRangeTest < ActiveRecord::TestCase
     self.use_transactional_fixtures = false
-    include PostgresqlHelper
-
-    teardown do
-      @connection.execute 'DROP TABLE IF EXISTS postgresql_ranges'
-      @connection.execute 'DROP TYPE IF EXISTS floatrange'
-      reset_pg_session
-    end
+    include ConnectionHelper
 
     def setup
       @connection = PostgresqlRange.connection
@@ -99,6 +93,12 @@ def setup
       @empty_range = PostgresqlRange.find(105)
     end
 
+    teardown do
+      @connection.execute 'DROP TABLE IF EXISTS postgresql_ranges'
+      @connection.execute 'DROP TYPE IF EXISTS floatrange'
+      reset_connection
+    end
+
     def test_data_type_of_range_types
       assert_equal :daterange, @first_range.column_for_attribute(:date_range).type
       assert_equal :numrange, @first_range.column_for_attribute(:num_range).type

activerecord/test/support/postgresql_helper.rb → activerecord/test/support/connection_helper.rb

-module PostgresqlHelper
-  # Make sure to drop all cached query plans to prevent invalid reference errors like:
-  #  cache lookup failed for type XYZ
-  def reset_pg_session
+module ConnectionHelper
+  def run_without_connection
+    original_connection = ActiveRecord::Base.remove_connection
+    yield original_connection
+  ensure
+    ActiveRecord::Base.establish_connection(original_connection)
+  end
+
+  # Used to drop all cache query plans in tests.
+  def reset_connection
     original_connection = ActiveRecord::Base.remove_connection
     ActiveRecord::Base.establish_connection(original_connection)
   end