Validation and Unit Testing

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

Verify text fields have content

• app/models/product.rb• validates :title, :description, :image_url, :prese

nse => true

• rails c– p = Product.new– p.valid? #=> false– p.errors

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

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

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

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

rake test

• 7 tests, 9 assertions, 2 failures, 0 errors, 0 skips

• Why are our tests failing?

• We added requirements for “valid” products

Update functional tests

• test/functional/products_controller_test.rb

@update = { :title => 'Lorem Ipsum', :description => 'Wibbles are fun', :image_url => 'lorem.jpg', :price => 19.95 }

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

rake test:units

• Runs only unit tests (not the full test suite)

• All unit tests pass!

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

Test your assumptions

• These tests pass now

• Do your tests fail if you remove the validation(s)?

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

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

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

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

Commit your work

• git status• git commit –a –m ‘Validation!’

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.

Upgrade to Rails 3.0.3

• vi Gemfile• bundle install• rake test