Spec::Rails, "model.should have(1).error_on(:attribute)" passes when?

Spec::Rails people, I'm curious about:   - model.should have(1).error_on(:attribute) displayed in the URL below:   http://rspec.rubyforge.org/rspec-rails/1.2.2/classes/Spec/Rails/Exten… The Rspec peepcode screencast suggests that model.should have(1).error_on(:attribute) should pass if model.send(:attribute) returns nil For me, I get an exception from the rspec script. My work-around is simple. Instead of:   - model.should have(1).error_on(:attribute) I Use:   -model.send(:attribute).should be_nil But now I have the question:   - What kind of error causes:     - model.should have(1).error_on(:attribute)     - to pass ?? --b