Ignore fixtures in test cases if there are no database configurations. References #5497.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4603 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/lib/active_record/fixtures.rb

@@ -505,7 +505,7 @@ def use_transactional_fixtures?
       end
 
       def setup_with_fixtures
-        return unless defined?(ActiveRecord::Base)
+        return unless defined?(ActiveRecord::Base) && !ActiveRecord::Base.configurations.blank?
 
         if pre_loaded_fixtures && !use_transactional_fixtures
           raise RuntimeError, 'pre_loaded_fixtures requires use_transactional_fixtures' 
@@ -537,7 +537,7 @@ def setup_with_fixtures
       alias_method :setup, :setup_with_fixtures
 
       def teardown_with_fixtures
-        return unless defined?(ActiveRecord::Base)
+        return unless defined?(ActiveRecord::Base) && !ActiveRecord::Base.configurations.blank?
 
         # Rollback changes.
         if use_transactional_fixtures?