Pt-E-2
Activity Description
Add unit tests which add unique products and duplicate products. Note that you will need to modify the fixture to refer to products and carts by name, for example product: ruby.
Author’s Solutions
Solution – search for “Test both unique and duplicate products”
Readers’ Solutions
Long says
My attempt:
In test/unit/cart_test.rb:
def new_cart_with_one_product(product_name)
cart = Cart.create
cart.add_product(products(product_name).id)
cart
end
test 'cart should create a new line item when adding a new product' do
cart = new_cart_with_one_product(:one)
assert_equal 1, cart.line_items.count
# Add a new product
cart.add_product(products(:ruby).id)
assert_equal 2, cart.line_items.count
end
test 'cart should update an existing line item when adding an existing product' do
cart = new_cart_with_one_product(:one)
# Re-add the same product
cart.add_product(products(:one).id)
assert_equal 1, cart.line_items.count
end
Arun says
I am doubtful whether the question was about creating a new and duplicate line items or products. I thought the answer is along the lines of
test "unique_product_should_be_saved"
product = Product.new(:title => "unique-title",
:description => "a unique product",
:image_url => "unique.png",
:price => 22)
assert product.save
end
test "non_unique_product_should_error_out"
product = Product.new(:title => "unique-title",
:description => "a unique product",
:image_url => "unique.png",
:price => 22)
assert !product.save
assert_equal "has not been saved since it is a duplicate ", product.errors[:title].join('; ')
end
Doc says
File: test/unit/cart_test.rb
require 'test_helper'
class CartTest < ActiveSupport::TestCase
test "cart line item should save price" do
cart = carts(:cart1)
[:ruby, :loremipsum, :ruby].each do |which_product|
product = products(which_product)
item = cart.add_product product.id
assert_equal item.price, product.price,
"cart line item did not save price"
end
end
test "cart line item quantity should increment" do
cart = carts(:cart2)
product = products(:ruby)
multiple = 3
multiple.times { cart.add_product product.id }
item = cart.line_items.find_by_product_id product.id
assert_equal multiple, item.quantity,
"cart line item quantity is incorrect"
end
test "cart line item price should equal most-recent price" do
cart = carts(:cart3)
product = products(:ruby)
sale_price = 0.8 * product.price
[product.price, sale_price, 100].each do |price|
cart.add_product product.id, price
item = cart.line_items.find_by_product_id product.id
assert_equal price, item.price,
"price #{item.price} is incorrect; should be #{price}"
end
end
test "cart should be created and destroyed" do
assert_same Cart.count, Cart.destroy_all.count,
"unable to destroy existing carts"
Cart.create
assert_equal 1, Cart.count, "unable to create cart"
assert_equal 1, Cart.destroy_all.count, "unable to destroy cart"
end
end
...
one: {}
cart1: {}
cart2: {}
cart3: {}
Updating Cart
Worth mentioning that there’s an error in one of these previous posts. It should be “assert_equal XXX, @cart.line_items.length” not count…..
Sean says
Doc,
Try using
multiple.times { cart.add_product(product.id).save! }
multiple.times { cart.add_product product.id }
Kamesh says
I was trying to add an additional test to products_controller_test to test the deletion of product in the cart, a point to note is that when i had the test case as shown below (as mentioned in the Solutions part), my functional tests failed
test "can't delete a product in cart" do
assert_difference('Product.count', 0) do
delete :destroy, :id => products(:ruby).to_param
end
assert_redirected_to products_path
end
test "can't delete a product in cart" do
assert_difference('Product.count', 0) do
cart = Cart.new
cart.add_product(products(:ruby).id,products(:ruby).price).save!
delete :destroy, :id => products(:ruby).to_param
end
assert_redirected_to products_path
end
John says
I thought I would share my result
In test/fixtures/carts.yml:
cart1:
id: 1
cart2:
id: 2
o1_coffee:
product_id: 2
cart_id: 1
quantity: 2
price: 36.00
o1_ruby:
product_id: 3
cart_id: 1
quantity: 2
price: 49.95
o1_rails:
product_id: 4
cart_id: 1
quantity: 2
price: 34.95
o2_ruby:
product_id: 3
cart_id: 2
quantity: 1
price: 49.95
one:
id: 7
title: One
description: MyText
image_url: MyString
price: 9.99
two:
id: 6
title: Two
description: MyText
image_url: MyString
price: 9.99
coffee:
id: 2
title: CoffeeScript
description:
<p>
CoffeeScript is JavaScript done right. It provides all of JavaScripts
functionality wrapped in a cleaner, more succinct syntax. In the first
book on this exciting new language, CoffeeScript guru Trevor Burnham
shows you how to hold onto all the power and flexibility of JavaScript
while writing clearer, cleaner, and safer code.
</p>
image_url: cs.jpg
price: 36.00
ruby:
id: 3
title: Programming Ruby 1.9
description:
<p>
Ruby is the fastest growing and most exciting dynamic
language out there. If you need to get working programs
delivered fast, you should add Ruby to your toolbox.
</p>
image_url: ruby.jpg
price: 49.95
rails:
id: 4
title: Rails Test Prescriptions
description:
<p>
<em>Rails Test Prescriptions</em> is a comprehensive guide to testing
Rails applications, covering Test-Driven Development from both a
theoretical perspective (why to test) and from a practical perspective
(how to test effectively). It covers the core Rails testing tools and
procedures for Rails 2 and Rails 3, and introduces popular add-ons,
including Cucumber, Shoulda, Machinist, Mocha, and Rcov.
</p>
image_url: rtp.jpg
price: 34.95
Use assigns to hook instance variables after a POST CREATE.
In test/functional/line_items_controller_test.rb:
test "One cart per session - The cart already exists" do
assert_no_difference('Cart.count') do
post :create, {product_id: products(:ruby).id}, {'cart_id' => '1'}
end
assert_equal "1", session[:cart_id]
assert_redirected_to store_url
end
test "One cart per session - Create a new cart" do
assert_difference('Cart.count', 1) do
post :create, product_id: products(:ruby).id
end
assert_redirected_to store_url
end
test "Validate existing carts" do
tests = [
[:coffee, :o1_coffee,"108.00", 'cart1'],
[:ruby, :o1_ruby, "149.85", 'cart1'],
[:rails, :o1_rails, "104.85", 'cart1'],
[:coffee, :o2_coffee, "36.00", 'cart2'],
[:ruby, :o2_ruby, "99.90", 'cart2']
].each do |t|
# Note :o2_coffee doesn't exist
# Validate t[1] exists in the database or POST created it!
begin
quantity = line_items(t[1]).quantity
rescue
quantity = 0
end
# Validate the products test database (fixture import)
assert products(t[0])
# Validate the carts test database (fixture import)
assert carts(t[3])
# Validate a product selection does not change the cart
assert_no_difference('Cart.count') do
post :create, {product_id: products(t[0]).id}, {'cart_id' => carts(t[3]).id.to_s}
end
# Validate the cart id set in the test database (fixture import) is the
# cart id from post
# ASSUMES @cart.id not altered in POST!!!! But this should never happen!
assert_equal carts(t[3]).id, assigns["cart"].id
# Validate choosing a product added 1 to its quantity
assert_equal quantity+1, assigns["line_item"].quantity
# Validate the product line_item total_price increases by the
# product price - t[2] reflects the price increase
assert_equal t[2], "%.2f" % assigns["line_item"].total_price
end
end