Good question. I'm not sure why, but without the underscore some tests failed.

```
1) Project#broken_or_success?
     Failure/Error: project.stub(:broken?).and_return(false)
     ArgumentError:
       wrong number of arguments (1 for 0)
     # ./app/models/project.rb:47:in `block in <class:Project>'
     # ./spec/models/project_spec.rb:113:in `block (3 levels) in <top (required)>'

...
```