Passing object parameters to urls in tests

I am wondering how to pass parameters to route declarations. I have an
app where one project belongs to a user. In one of my integration tests,
I want to check that the template being rendered is the one where the
“logged in user” can register a project:

get new_user_project_path(:user) #does not work
#assert_template ‘/users/:id/project/new’ #id must be this user’s id,
assert_template ‘projects/new’ #true, but must be /user/:id/project/new

rake routes says:

POST /users/:user_id/project
{:action=>“create”, :controller=>“projects”}

new_user_project GET /users/:user_id/project/new
{:action=>“new”, :controller=>“projects”}