Question

Having read this:
"No route matches" error?

I’m trying to figure out if there is a gem or way to monkey patch actionpack to get around this constraint.

Basically, I’m writing specs (they run fast), and I don’t understand why actionpack throws this error when being applied to an object which isn’t “saved”.

For two reasons:

1. Why is it throwing a “No route matches” when it really should be throwing something more meaningful (e.g. object must be saved before a route can be constructed, or object ID is nil). The exception seems a little obscure.
2. I shouldn’t have to save the object at all if all I am trying to do is generate a url for that object, given the ID is populated using a factory or something similar.

This constraint makes it a pain to write fast tests, unless I’m missing something…

Answer 1

True, the error message is a bit obscure. Regarding your second point, you don’t need to save an object to generate a URL, the helper will work just as well with a literal value.

building_path(1) # GET /buildings/1 => BuildingsController#show, params={:id=>"1"}

So in the example the object can be replaced with any value:

get :show, :id => "1"

For example, if you use rails generate scaffold Article, RSpec will build a spec like this:

  def mock_article(stubs={})
    (@mock_article ||= mock_model(Article).as_null_object).tap do |article|
      article.stub(stubs) unless stubs.empty?
    end
  end

  describe "GET show" do
    it "assigns the requested article as @article" do
      Article.stub(:find).with("37") { mock_article }
      get :show, :id => "37"
      assigns(:article).should be(mock_article)
    end
  end

which does not hit the database.