Rspec actions that change the DB

I'm a bit confused with the behavior of rpsec tests involving controller methods that affect the DB. I have seen many examples of rspec tests that involve POST's and DELETE's where people check to see that an object was created or deleted. In most of these tests people are able to just check that the count of the model in the DB has increased or descreased with a tests such as:

delete :clear_photos, :id => @album.id
@album.photos.size.should == 0 

or with lambdas:

lambda {delete :destroy, :id => @photo.id}.should change(@album.photos, :size).by(-1)

The syntax isn't perfect in the last example but my point is that in my experience, I have needed to call reload on the object in order for any of these tests to pass, but for some reason, other are able to make them work without explicitly calling reload. Something about calling reload every time I am testing a db create/destroy action seems fishy to me.

Can anyone help me understand what's going on? Thanks!

ACTUAL CODE UPDATE

it "should cl开发者_如何学编程ear all photos for an album" do
  @album = Factory(:album, :photos => [Factory(:photo), Factory(:photo)])
  delete :clear, :album_id => @album.id
  @album.photo_count.should == 0
end

I get this response:

'PhotosController#clear should clear all photos for an album' FAILED
expected: 0,
     got: 2 (using ==)
./spec/controllers/photos_controller_spec.rb:17:

If I reload the @album before calling photo_count though, it works.

I would like to point out that testing a model state in a controller spec is not a very good practice, because it violates the isolation of a unit test. You should instead test if a controller response is appropriate for the current scenario.