Mongoid + Cucumber - ruby-on-rails

Question

I try to run a scenario with Cucumber, through Capybara, in a Rails 3.2.3 app supported by Mongoid. The aim is to have current user add a book to his collection.
Everything goes ok, but the final step definition, where I check that the amount of books is now one, fails.
But if I check on the app controller, the size actually increased. And actually, when I send reload to the user in the step definition, it passes:
user.reload.books(true).size.should == 1
I'm afraid this behavior could harm my app once in production. Any advice how to make sure all tests and app behaviors are consistent?
UPDATE
I checked the test.log to see what's going on.
Calling reload I get this query to MongoDB:
find({"count"=>"books",
"query"=>{:_id=>{"$in"=>[BSON::ObjectId('4f889b473dffd63235000004')]}},
"fields"=>nil}).limit(-1)
while without the reload I get this:
find({"count"=>"books", "query"=>{:_id=>{"$in"=>[]}}, "fields"=>nil}).limit(-1)
It practically doesn't query against the user if I don't reload the model, which doesn't make much sense to me.

Answer 1

The following works for me (updated with actual Cucumber example)
I built a Rails project to test out your issue, rails 3.2.3, mongoid 2.4.8, mongo 1.6.2, mongodb 2.0.4, cucumber 1.1.9.
The following (association generated methods) work as expected, without need for refresh:
user.books << book
book.users << user
Then I tried to bypass the association, which was what I thought that you were doing.
user.push(:book_ids, book.id)
book.push(:user_ids, user.id)
These DO bypass the association, resulting in incomplete (one-way instead of two-way) references, but the memory and db state is consistent. So my guess in my previous answer about what you were experiencing was wrong, there's no refresh needed and you are probably doing something else. Note that you/we do not want the incomplete references, please do not push directly to the internals for Mongoid referenced relations.
Are you using the association append "<<" for adding a user or a book? My current conclusion is that Mongoid referenced relations work as advertized for my test of your issue. There's no need for refresh.
Here's the model:
class User
include Mongoid::Document
field :first_name, type: String
field :last_name, type: String
has_and_belongs_to_many :books
end
class Book
include Mongoid::Document
field :title, type: String
field :author, type: String
has_and_belongs_to_many :users
end
Cucumber feature
Feature: UserAndBook
Test adding a book to a user_s books
Scenario: add_book_to_user
Given starting with no users and no books
And a new user
And that the new user has no books
And a new book
And add book to user
Then I can check that the user has a book
Cucumber steps
require 'test/unit/assertions'
require File.expand_path('../../../test/test_helper', __FILE__)
World(Test::Unit::Assertions)
Given 'starting with no users and no books' do
User.delete_all
Book.delete_all
assert_equal(0, User.count)
assert_equal(0, Book.count)
end
Given 'a new user' do
#user = User.create(first_name: 'Gary', last_name: 'Murakami')
end
Given 'that the new user has no books' do
assert_equal(0, #user.books.count)
end
Given 'a new book' do
#book = Book.create(title: 'A Tale of Two Cities', author: 'Charles Dickens')
end
Given 'add book to user' do
#user.books << #book
end
Then 'I can check that the user has a book' do
assert_equal(1, #user.books.count)
end
I'm open to further exchange of info to help to address your issue.
Blessings,
-Gary
P.S. Looking at the log, it is interesting to see that user.books.length does an actual db "find count $in" query rather than a local array length.
Previous answer
You've pretty much answered your own question. In Rails, you need to use the reload method whenever data for your model has changed in the database, otherwise you will just be looking at the previously loaded/instantiated/cached state of your model. With update of just an attribute, things look pretty consistent, but associations are more complicated and the inconsistency becomes more obvious.