The rails-3.0.1 release excluded a change that I had naively expected to be included. This upgrade is only necessary if you write view specs and are upgrading to rails-3.0.1. To upgrade, all you need to do is change your Gemfile to read:
gem "rspec-rails", "2.0.1"
And then run
bundle update rspec-rails
## Release Notes
### 2.0.1 / 2010-10-15
* Add option to not generate request spec (--skip-request-specs)
* Bug fixes
* Updated the mock_[model] method generated in controller specs so it adds
any stubs submitted each time it is called.
* Fixed bug where view assigns weren't making it to the view in view specs in Rails-3.0.1.