Print out information about whether the identity map is on or off when running unit tests

activerecord/RUNNING_UNIT_TESTS

@@ -25,3 +25,10 @@ You can run all the tests for a given database via rake:
   $ rake test_mysql
 
 The 'rake test' task will run all the tests for mysql, mysql2, sqlite3 and postgresql.
+
+== Identity Map
+
+By default the tests run with the Identity Map turned off. But all tests should pass whether or
+not the identity map is on or off. You can turn it on using the IM env variable:
+
+  $ IM=true ruby -Itest test/case/base_test.rb

activerecord/test/cases/helper.rb

@@ -12,19 +12,20 @@ require 'active_support/dependencies'
 require 'support/config'
 require 'support/connection'
 
-ARTest.connect
-
 # TODO: Move all these random hacks into the ARTest namespace and into the support/ dir
 
 # Show backtraces for deprecated behavior for quicker cleanup.
 ActiveSupport::Deprecation.debug = true
 
-# Quote "type" if it's a reserved word for the current connection.
-QUOTED_TYPE = ActiveRecord::Base.connection.quote_column_name('type')
-
 # Enable Identity Map only when ENV['IM'] is set to "true"
 ActiveRecord::IdentityMap.enabled = (ENV['IM'] == "true")
 
+# Connect to the database
+ARTest.connect
+
+# Quote "type" if it's a reserved word for the current connection.
+QUOTED_TYPE = ActiveRecord::Base.connection.quote_column_name('type')
+
 def current_adapter?(*types)
   types.any? do |type|
     ActiveRecord::ConnectionAdapters.const_defined?(type) &&

activerecord/test/support/connection.rb

@@ -11,7 +11,7 @@ module ARTest
   end
 
   def self.connect
-    puts "Using #{connection_name}"
+    puts "Using #{connection_name} with Identity Map #{ActiveRecord::IdentityMap.enabled? ? 'on' : 'off'}"
     ActiveRecord::Base.logger = Logger.new("debug.log")
     ActiveRecord::Base.configurations = connection_config
     ActiveRecord::Base.establish_connection 'arunit'