Rails trouble writing integration test for uploading array of files - ruby-on-rails-4

Question

I'm having trouble getting an integration test to pass. A user creates a product, which can have many pictures. The product's new.html.erb contains file field <%= file_field_tag "images[]", type: :file, multiple: true %> The code works fine, I'm just having problems creating a working integration test.
products_creation_test.rb:
require 'test_helper'
class ProductsCreationTest < ActionDispatch::IntegrationTest
.
.
.
test "should create new product with valid info" do
log_in_as(#user)
pic1 = fixture_file_upload('test/fixtures/cat1.jpg', 'image/jpg')
pic2 = fixture_file_upload('test/fixtures/profile.png', 'image/png')
assert_difference 'Product.count', 1 do
post user_products_path(#user), product: { title: 'test',
description: 'test',
price: '5.99',
images: [pic1, pic2] }
end
assert_redirected_to #user
#user.reload
newprod = #user.products.last
pics = newprod.pictures.all
assert_equal 2, pics.count
end
end
This fails the last assertion, stating that there are no pictures associated with the new product, when there should be 2. inspecting the pics variable, i get the following error: RuntimeError: #<ActiveRecord::AssociationRelation []
What am I missing?
my model structure is as follows:
User has_many Products, Products has_many Pictures
products_controller.rb:
class ProductsController < ApplicationController
before_action :valid_user, only: [:new, :create, :edit, :update]
.
.
.
def create
#product = current_user.products.build(product_params)
if #product.save
# to handle multiple images upload on create
if params[:images]
params[:images].each { |image|
#product.pictures.create(image: image)
}
end
flash[:success] = "Product Created!"
redirect_to current_user
else
flash[:alert] = "Something went wrong."
render :new
end
end
.
.
.
end
pictures_controller.rb:
class PicturesController < ApplicationController
def create
#picture = Picture.new(picture_params)
#picture.save
end
def destroy
end
private
def picture_params
params.require(:picture).permit(:product_id, :image, :_destroy)
end
end
picture.rb:
class Picture < ActiveRecord::Base
belongs_to :product
mount_uploader :image, PicturesUploader
validates_integrity_of :image
validates_processing_of :image
validates :image, file_size: { less_than: 10.megabytes }
end

Answer 1

Solved as follows:
revised products_creation_test.rb:
require 'test_helper'
class ProductsCreationTest < ActionDispatch::IntegrationTest
.
.
.
test "should create new product with valid info" do
log_in_as(#user)
pic1 = fixture_file_upload('test/fixtures/cat1.jpg', 'image/jpg')
pic2 = fixture_file_upload('test/fixtures/profile.png', 'image/png')
assert_difference 'Product.count', 1 do
post user_products_path(#user), product: { title: 'test',
description: 'test',
price: '5.99',
}, images: [pic1, pic2]
end
assert_redirected_to #user
newprod = assigns(:product)
assert_equal 2, newprod.pictures.count
end
end