1. Validation and Unit Testing

2. Validations
• Title should not be empty
• Description should not be empty
• Price should be valid
• Models hook the code up to what’s in the db
• Everything that is put into / read from the db
goes through the model

3. Verify text fields have content
• app/models/product.rb
• validates :title, :description, :image_url,
:presense => true
• rails c
– p = Product.new
– p.valid? #=> false
– p.errors

4. Validate price > $0.00
• app/models/product.rb
• validates :price, :numericality =>
{:greater_than_or_equal_to => 0.01}
• p = Product.new({:title => "blah", :description
=> "blah", :image_url => "blah"})
• p.valid?
• p.errors

5. Validate uniqueness of title
• app/model/product.rb
• validates :title, :uniqueness => true
• p = = Product.new({:title => "blah", :description
=> "blah", :image_url => "blah", :price => "33"})
• p.save
• q = Product.new({:title => "blah", :description =>
"blah", :image_url => "blah", :price => "33"})
• q.valid # => false
• q.errors

6. Validates :image_url
• validates :image_url, :format => {
:with => %r{.(gif|jpg|png)$}i,
:message => ‘must be a URL for GIF, JPG or PNG
image’
}
• q = Product.new({:title => "blah", :description =>
"blah", :image_url => "blah", :price => "33"})
• q.valid?
• q.errors

7. What we’ve accomplished
• Product model verifies:
– field’s title, description and image URL are not
empty
– Price is a valid number > $0.01
– Title is unique
– Image URL looks reasonable
• http://localhost:3000/products

8. rake test
• 7 tests, 9 assertions, 2 failures, 0 errors, 0
skips
• Why are our tests failing?
• We added requirements for “valid” products

9. Update functional tests
• test/functional/products_controller_test.rb
@update = {
:title => 'Lorem Ipsum',
:description => 'Wibbles are fun',
:image_url => 'lorem.jpg',
:price => 19.95
}

10. Model Unit Tests
• test/unit/product_test.rb
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

11. rake test:units
• Runs only unit tests (not the full test suite)
• All unit tests pass!

12. Test more validations
test "product price must be positive" do
product = Product.new(:title => "My Book", :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].join(': ')
product.price = 0
assert product.invalid?
assert_equal "must be greater than or equal to 0.01",
product.errors[:price].join(': ')
product.price = 1
assert product.valid?
end

13. Test your assumptions
• These tests pass now
• Do your tests fail if you remove the
validation(s)?

14. Good/Bad Image_url’s
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

15. Test Fixtures
• Fills our test database with known sample
data
• Usually stored in CSV or YAML format (YAML is
more common)
• Fixture name must match the table you’re
testing
• YAML requires spaces not tabs, tabs produce a
syntax error

16. Products Fixture
• test/fixtures/products.yml
ruby:
title: Programming Ruby 1.9
description:
Book on programming Ruby. Commonly called
the "pick-axe" book.
price: 49.50
image_url: ruby.png

17. Using Fixture Data
• test/unit/product_test.rb
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.save
assert_equal "has already been taken",
product.errors[:title].join('; ')
end

18. Commit your work
• git status
• git commit –a –m ‘Validation!’

19. Homework
• Add a validation that verifies the title is at least
10 characters long
– Checkout the :length argument to validate
• Add a validation that verifies the description is no
more than 50 characters long
• Change the error message on one or more of
your validations
• Pretend we operate a dollar store. Write a
validation that makes sure the price is between
$0.01 and $1.00.

20. Upgrade to Rails 3.0.3
• vi Gemfile
• bundle install
• rake test