This took a bit for us to figure out. The Integer extension doesn't attempt to coerce the type of the field coming back from Mongo.

If you insert into a collection via the mongo command line, the Mongoid model will render it as a float rather than an integer.

For instance:

db.bands.insert( { name: "Robin's Merry Men", album_count: 1 })

Have a model defined like so:

class Band
  include Mongoid::Document

  field :name, type: String
  field :album_count, type: Integer
end

Pull the object out:

band = Band.where( name: "Robin's Merry Men" ).first

Check the album coin

pp band.album_count

We'll get 1.0

It would probably be advantageous to have the Integer extension coerce the value returned to an integer if the field type has been defined that way?