as of press time, the google was not so hot on the following exception
NoMethodError: undefined method `each' for nil:NilClass activerecord (3.2.3) lib/active_record/fixtures.rb:862:in `teardown_fixtures' activesupport (3.2.3)
but it was killing me. the culprit? once upon a time, some clever person here read a blog post: The Road to Faster Tests on 37signals blog. and well, it worked wonders.
until Rails 3.2 came to our town, and this patch is no longer relevant, or working.