ActiveRecord - nil object when you didn't expect it

Hi,

I have the following code in a RoR project, models and tests are all in
the proper directories:

require File.dirname(FILE) + ‘/…/test_helper’

class GalleryTest < Test::Unit::TestCase
fixtures :galleries

@gallery = nil

def test_presence_of
@gallery = Gallery.new
@gallery.title = ‘My test gallery’
@gallery.nr = 123
image = Image.new(1, 100, ‘jpg’)
@gallery.images = Array.new
@gallery.images << image
@gallery.save

assert @gallery.valid?

end
end

class Gallery < ActiveRecord::Base
validates_presence_of :title, :nr, :images
validates_numericality_of :nr
validates_length_of :title, :in => 1…255

has_many :images
end

class Image < ActiveRecord::Base
validates_presence_of :nr, :sort_nr, :ext
validates_presence_of :sort_nr
validates_presence_of :ext

belongs_to :gallery

def initialize(nr, sort_nr, ext)
@nr = nr
@sort_nr = sort_nr
@ext = ext
end
end

When I run the gallery test file, ruby shows me the following error:

test_presence_of(GalleryTest):
NoMethodError: You have a nil object when you didn’t expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.[]
c:/program
files/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.6/lib/active_
record/base.rb:1871:in read_attribute' ... record/transactions.rb:121:intransaction’
c:/program
files/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.6/lib/active_
record/transactions.rb:129:in save' test/unit/gallery_test.rb:23:intest_presence_of’

It has something to do with gallery.images, but I can’t figure out how
to fix this.

Another question (offtopic): Why does it take 10 seconds for the test to
start running? This gets annoying when you want to “code a little, test
a little”.

On 15 May 2008, at 06:40, Aa Aa wrote:

@nr = nr
@sort_nr = sort_nr
@ext = ext
end
end

You’re overriding activerecord’s initialize function, but without
calling super, so stuff is not initialized properly (and thus crazy
stuff happens. In addition activerecord attributes are not persisted
as instance variables so you inititialize function doesn’t do what you
think it does. Why do you need a custom initialize at all ?

Another question (offtopic): Why does it take 10 seconds for the
test to
start running? This gets annoying when you want to “code a little,
test
a little”.
Probably because certain bits of ruby are a lot slower on windows
(there was another thread about this a day or 2 ago)

Fred

On 15 May 2008, at 11:01, Aa Aa wrote:

my_image.sort_nr = 1
my_image.ext = ‘jpg’

Is there another way to send arguments to initialize without doing an

Image.new :nr => 123, :sort_nr => 1, :ext => ‘jpg’

Fred

Frederick C. wrote:

On 15 May 2008, at 06:40, Aa Aa wrote:

@nr = nr
@sort_nr = sort_nr
@ext = ext
end
end

You’re overriding activerecord’s initialize function, but without
calling super, so stuff is not initialized properly (and thus crazy
stuff happens. In addition activerecord attributes are not persisted
as instance variables so you inititialize function doesn’t do what you
think it does. Why do you need a custom initialize at all ?

Another question (offtopic): Why does it take 10 seconds for the
test to
start running? This gets annoying when you want to “code a little,
test
a little”.
Probably because certain bits of ruby are a lot slower on windows
(there was another thread about this a day or 2 ago)

Fred

Can’t test it right now, but super could be the issue indeed. I did a
initialize override so I could do this

my_image = Image.New(123, 1, ‘jpg’)

instead of

my_image = Image.New
my_image.nr = 123
my_image.sort_nr = 1
my_image.ext = ‘jpg’

Is there another way to send arguments to initialize without doing an
override?

Frederick C. wrote:

On 15 May 2008, at 11:01, Aa Aa wrote:

my_image.sort_nr = 1
my_image.ext = ‘jpg’

Is there another way to send arguments to initialize without doing an

Image.new :nr => 123, :sort_nr => 1, :ext => ‘jpg’

Fred

Thanks Fred, the test is working now. I’ve removed the initialize and
used the => thing instead.

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