uninitialized constant ActionDispatch::Integration::Session::Test

When trying to run cucumber from a rails 3 app a NameError is raised by ActionDispatch::Integration::Session

I fixed this by simple adding a:
require 'test/unit/assertions'

This might be a naive fix (should const_missing handle this?), but it seems consistent with other with other testing classes that also explicitly requires parts of test/unit.

I have attached a patch.