diff --git a/actionmailer/test/abstract_unit.rb b/actionmailer/test/abstract_unit.rb
index c705f1c8bd..75690b49ad 100644
--- a/actionmailer/test/abstract_unit.rb
+++ b/actionmailer/test/abstract_unit.rb
@@ -3,5 +3,8 @@ require 'test/unit'
 $:.unshift "#{File.dirname(__FILE__)}/../lib"
 require 'action_mailer'
 
+# Show backtraces for deprecated behavior for quicker cleanup.
+ActiveSupport::Deprecation.debug = true
+
 $:.unshift "#{File.dirname(__FILE__)}/fixtures/helpers"
 ActionMailer::Base.template_root = "#{File.dirname(__FILE__)}/fixtures"
diff --git a/actionpack/test/abstract_unit.rb b/actionpack/test/abstract_unit.rb
index 4d858dfa0c..de4ca439f4 100644
--- a/actionpack/test/abstract_unit.rb
+++ b/actionpack/test/abstract_unit.rb
@@ -8,6 +8,9 @@ require 'action_controller'
 require 'breakpoint'
 require 'action_controller/test_process'
 
+# Show backtraces for deprecated behavior for quicker cleanup.
+ActiveSupport::Deprecation.debug = true
+
 ActionController::Base.logger = nil
 ActionController::Base.ignore_missing_templates = false
-ActionController::Routing::Routes.reload rescue nil
\ No newline at end of file
+ActionController::Routing::Routes.reload rescue nil
diff --git a/actionwebservice/test/abstract_unit.rb b/actionwebservice/test/abstract_unit.rb
index 3c5a973498..b7088c43f3 100644
--- a/actionwebservice/test/abstract_unit.rb
+++ b/actionwebservice/test/abstract_unit.rb
@@ -9,6 +9,10 @@ require 'action_web_service'
 require 'action_controller'
 require 'action_controller/test_process'
 
+# Show backtraces for deprecated behavior for quicker cleanup.
+ActiveSupport::Deprecation.debug = true
+
+
 ActionController::Base.logger = Logger.new("debug.log")
 ActionController::Base.ignore_missing_templates = true
 
diff --git a/activerecord/test/abstract_unit.rb b/activerecord/test/abstract_unit.rb
index f30e190fc9..5108988a88 100755
--- a/activerecord/test/abstract_unit.rb
+++ b/activerecord/test/abstract_unit.rb
@@ -8,6 +8,10 @@ require 'active_support/binding_of_caller'
 require 'active_support/breakpoint'
 require 'connection'
 
+# Show backtraces for deprecated behavior for quicker cleanup.
+ActiveSupport::Deprecation.debug = true
+
+
 QUOTED_TYPE = ActiveRecord::Base.connection.quote_column_name('type') unless Object.const_defined?(:QUOTED_TYPE)
 
 class Test::Unit::TestCase #:nodoc:
diff --git a/activesupport/test/abstract_unit.rb b/activesupport/test/abstract_unit.rb
index 7e3ff50ac9..8e237beac2 100644
--- a/activesupport/test/abstract_unit.rb
+++ b/activesupport/test/abstract_unit.rb
@@ -2,3 +2,6 @@ require 'test/unit'
 
 $:.unshift "#{File.dirname(__FILE__)}/../lib"
 require 'active_support'
+
+# Show backtraces for deprecated behavior for quicker cleanup.
+ActiveSupport::Deprecation.debug = true