diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index fcb32681de0ffe0c104d293f123d31e59937af94..f0bf07e65b1afd1bf37b5d08cdf9bbd40c7e598b 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Make the Fixtures Test::Unit enhancements more supporting for double-loaded test cases.  Closes #10379 [brynary]
+
 * Fix that validates_acceptance_of still works for non-existent tables (useful for bootstrapping new databases).  Closes #10474 [hasmanyjosh]
 
 * Ensure that the :uniq option for has_many :through associations retains the order.  #10463 [remvee]
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 7a00b5bb568eddaafae2896f1cf11deb67ebee62..0da8c514d7fd55372990c928e0a3b6a0bd36cb79 100755
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -916,6 +916,8 @@ def use_transactional_fixtures?
       end
 
       def setup_with_fixtures
+        return if @fixtures_setup
+        @fixtures_setup = true
         return unless defined?(ActiveRecord::Base) && !ActiveRecord::Base.configurations.blank?
 
         if pre_loaded_fixtures && !use_transactional_fixtures
@@ -947,6 +949,8 @@ def setup_with_fixtures
       alias_method :setup, :setup_with_fixtures
 
       def teardown_with_fixtures
+        return if @fixtures_teardown
+        @fixtures_teardown = true
         return unless defined?(ActiveRecord::Base) && !ActiveRecord::Base.configurations.blank?
 
         unless use_transactional_fixtures?
@@ -963,24 +967,31 @@ def teardown_with_fixtures
       alias_method :teardown, :teardown_with_fixtures
 
       def self.method_added(method)
+        return if @__disable_method_added__
+        @__disable_method_added__ = true
+        
         case method.to_s
         when 'setup'
           unless method_defined?(:setup_without_fixtures)
             alias_method :setup_without_fixtures, :setup
-            define_method(:setup) do
+            define_method(:full_setup) do
               setup_with_fixtures
               setup_without_fixtures
             end
           end
+          alias_method :setup, :full_setup
         when 'teardown'
           unless method_defined?(:teardown_without_fixtures)
             alias_method :teardown_without_fixtures, :teardown
-            define_method(:teardown) do
+            define_method(:full_teardown) do
               teardown_without_fixtures
               teardown_with_fixtures
             end
           end
+          alias_method :teardown, :full_teardown
         end
+        
+        @__disable_method_added__ = false
       end
 
       private
diff --git a/activerecord/test/fixtures_test.rb b/activerecord/test/fixtures_test.rb
index c1e79b807f427b6a8fcfa3a698e771e7e4cd146f..deeb391e3ad86c8f0ad5ac9a941a7bdf99857ca6 100755
--- a/activerecord/test/fixtures_test.rb
+++ b/activerecord/test/fixtures_test.rb
@@ -324,6 +324,22 @@ def test_fixture_table_names
   end
 end
 
+# This is to reproduce a bug where if a TestCase is loaded
+# twice by Ruby, it loses its fixture setup hook.
+class_def = <<-CODE
+  class DoubleLoadedTestCase < Test::Unit::TestCase
+    fixtures :topics
+
+    def setup
+    end
+  
+    def test_should_properly_setup_fixtures
+      assert_nothing_raised { topics(:first) }
+    end
+  end
+CODE
+2.times { eval(class_def) }
+
 class OverlappingFixturesTest < Test::Unit::TestCase
   fixtures :topics, :developers
   fixtures :developers, :accounts