title: RSpec passing object as a param in a controller_spec
body: <p>I have a users_controller_spec.rb with this:</p>
  
  <pre><code>describe "POST create" do
    describe "with valid params" do
      let(:user) { create(:user) }
  
      it "assigns a newly created user as @user" do
        post :create, user: user
        assigns(:user).should be_a(User)
        assigns(:user).should be_persisted
      end
    end
  
   ...
  
  end
  </code></pre>
  
  <p>Debuggin I found that the controller receive the next params</p>
  
  <pre><code>(rdb:1) pp params
  {"user"=&gt;"1", "controller"=&gt;"users", "action"=&gt;"create"}
  </code></pre>
  
  <p>Why "user" => "1" ?, why is not passing the user object properly ? </p>