If you are doing a good job of testing all the code you write in a rails
project, then most of your code files should be paired with test (or spec)
files. You can think of these as alternate files. The alternate file of
user.rb is user_spec.rb and vice versa.
The vim-rails plugin makes it easy
to jump back and forth between alternate files. Enter :A and you will go
to the alternate file of the current file. This makes a common navigation
path for rails projects all the more efficient.