diff --git a/activesupport/lib/active_support/test_case.rb b/activesupport/lib/active_support/test_case.rb
index 0f531b0c799914041942183107c8d930bbe426df..197e73b3e85ec9195d8d3a16f9a84d5c84cf73e9 100644
--- a/activesupport/lib/active_support/test_case.rb
+++ b/activesupport/lib/active_support/test_case.rb
@@ -12,7 +12,13 @@ def self.test(name, &block)
       test_name = "test_#{name.gsub(/\s+/,'_')}".to_sym
       defined = instance_method(test_name) rescue false
       raise "#{test_name} is already defined in #{self}" if defined
-      define_method(test_name, &block)
+      if block_given?
+        define_method(test_name, &block)
+      else
+        define_method(test_name) do
+          flunk "No implementation provided for #{name}"
+        end
+      end
     end
   end
 end