Spec Error: "undefined method `id' for nil:NilClass". The hacky workaround is not working for me.

The error refers to spec/controllers/users_controller_spec.rb as discussed in the first few minutes of this video.

it "sets the session user_id to the created user" do
  post :create, {:user => valid_attributes}, valid_session
  expect(session[:user_id]).to eq(User.find_by(email: valid_attributes["email"]).id)
end

$ bin/rspec --format=documentation spec/controllers/users_controller_spec.rb

  1) UsersController POST create with valid params sets the session user_id to the created user
     Failure/Error: expect(session[:user_id]).to eq(User.find_by(email: valid_attributes["email"]).id)
     NoMethodError:
       undefined method `id' for nil:NilClass
     # ./spec/controllers/users_controller_spec.rb:103:in `block (4 levels) in <top (required)>'

I can only assume that for some reason it doesn't know that a User has an id.

I suspect I'm getting this error because earlier in the course I updated the rspec gem to get around another error. I've been able to work past all the other little problems this update has caused, but this one is beyond me. A google search indicated that stubbing might help get past it, but I really can't figure out how stubbing works.

Ruby v2.0
Rails v4.0.1
Full project code: git@bitbucket.org:GeoffreyEmerson/odot.git