Agile Web Development with Rails, Edition 4

7.3 Playtime 7.1 Iteration B1: Validation and Unit Testing

7.2 Iteration B2: Unit Testing

Introduce the importance of unit testing.

Look at what files are generated

ls test/unit
helpers
product_test.rb

Add some unit tests for new function.

edit test/unit/product_test.rb
require 'test_helper'
 
class ProductTest < ActiveSupport::TestCase
  test "product attributes must not be empty" do
    product = Product.new
    assert product.invalid?
    assert product.errors[:title].any?
    assert product.errors[:description].any?
    assert product.errors[:price].any?
    assert product.errors[:image_url].any?
  end
 
  test "product price must be positive" do
    product = Product.new(title:       "My Book Title",
                          description: "yyy",
                          image_url:   "zzz.jpg")
    product.price = -1
    assert product.invalid?
    assert_equal ["must be greater than or equal to 0.01"],
      product.errors[:price]
 
    product.price = 0
    assert product.invalid?
    assert_equal ["must be greater than or equal to 0.01"], 
      product.errors[:price]
 
    product.price = 1
    assert product.valid?
  end
 
  def new_product(image_url)
    Product.new(title:       "My Book Title",
                description: "yyy",
                price:       1,
                image_url:   image_url)
  end
 
  test "image url" do
    ok = %w{ fred.gif fred.jpg fred.png FRED.JPG FRED.Jpg
             http://a.b.c/x/y/z/fred.gif }
    bad = %w{ fred.doc fred.gif/more fred.gif.more }
    
    ok.each do |name|
      assert new_product(name).valid?, "#{name} shouldn't be invalid"
    end
 
    bad.each do |name|
      assert new_product(name).invalid?, "#{name} shouldn't be valid"
    end
  end
 
  test "product is not valid without a unique title" do
    product = Product.new(title:       products(:ruby).title,
                          description: "yyy", 
                          price:       1, 
                          image_url:   "fred.gif")
 
    assert product.invalid?
    assert_equal ["has already been taken"], product.errors[:title]
  end
 
  test "product is not valid without a unique title - i18n" do
    product = Product.new(title:       products(:ruby).title,
                          description: "yyy", 
                          price:       1, 
                          image_url:   "fred.gif")
 
    assert product.invalid?
    assert_equal [I18n.translate('activerecord.errors.messages.taken')],
                 product.errors[:title]
  end
  
end

Look at existing test data

edit test/fixtures/products.yml
# Read about fixtures at
# http://api.rubyonrails.org/classes/ActiveRecord/Fixtures.html
 
one:
  title: MyString
  description: MyText
  image_url: MyString
  price: 9.99
 
two:
  title: MyString
  description: MyText
  image_url: MyString
  price: 9.99

Add a fixture.

edit test/fixtures/products.yml
# Read about fixtures at
# http://api.rubyonrails.org/classes/ActiveRecord/Fixtures.html
 
one:
  title: MyString
  description: MyText
  image_url: MyString
  price: 9.99
 
two:
  title: MyString
  description: MyText
  image_url: MyString
  price: 9.99
 
ruby: 
  title:       Programming Ruby 1.9
  description: 
    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.
  price:       49.50
  image_url:   ruby.png 

Tests pass!

rake test:units
Run options: 
 
# Running tests:
 
.....
 
Finished tests in 0.093294s, 53.5942 tests/s, 246.5335 assertions/s.
 
5 tests, 23 assertions, 0 failures, 0 errors, 0 skips
 
ruby -v: ruby 2.1.5p273 (2014-11-13 revision 48405) [x86_64-linux]

7.3 Playtime 7.1 Iteration B1: Validation and Unit Testing