I keep getting the error “No route matches { :controller => "whatever”, :action => “whatever” }“ when testing Rails applications with RSpec. Everytime I do, I spend a while tracking it down. This time I decided to document what I did, so I can get on with life.

Turns out it’s because it was a nested resource, and I hadn’t passed the parent ID. Instead of this:

describe ContactUserController do
  context "when not logged in" do
    before(:each) { get :show }
    it_should_behave_like "an unauthenticated action"
  end
end

I needed:

describe ContactUserController do
  context "when not logged in" do
    before(:each) { get :show, :user_id => "ExampleUser" }
    it_should_behave_like "an unauthenticated action"
  end
end

And now it works. Slightly embarrasing, but hopefully it’ll help someone. Maybe even me when my short term memory causes me to forget it again.