View abstraction for integration testing
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View abstraction for integration testing


To create a basic Domino class, inherit from Domino and define a selector and attributes:

module Dom
  class Post < Domino
    selector '#posts .post'
    attribute :title # selector defaults to .title
    attribute :author_name # selector defaults to .author-name
    attribute :body, '.post-body' # example of selector override

    # pass a block if you want to convert the value
    attribute :comments do |text|

    attribute :posted_at do |text|

    # Combination selector is a boolean that combines with the root node. Boolean.
    # You can find a post that also has the .active class.
    attribute :active, "&.active"

    # Combination selector for a data attribute. Finds the value of the data attribute
    # on the root node. You can convert it with a callback like any other attribute.
    attribute :rating, "&[data-rating]", &:to_i

    # Combination selector for a data attribute with no value set. Must convert to
    # boolean in the callback.
    attribute :blah, "&[data-blah]" do |a|

Now in your integration test you can use some of Domino's methods:

assert_equal 4, Dom::Post.count
refute_nil Dom::Post.find_by_title('First Post')

# Find by attribute yields the node when using a block.
assert_equal Dom::Post.find_by_title { |node| node.text == "First Post" && node.tag_name == 'p' }

# Multiple attributes, returns first match if any
refute_nil Dom::Post.find_by(title: 'First Post', author: 'Jane Doe')

# Multiple attributes with exception if no match is found
refute_nil Dom::Post.find_by!(title: 'First Post', author: 'Jane Doe')

# Multiple attributes, returns all matches if any
assert_equal ["12/06/2014", "12/01/2014"], Dom::Post.where(author: 'Jane Doe').map(&:posted_on)

What makes it really powerful is defining scoped actions:

module Dom
  class Post < Domino
    def delete
      within(id) { click_button 'Delete' }

refute_nil Dom::Post.find_by_title('First Post')
Dom::Post.find_by_title('First Post').delete
assert_nil Dom::Post.find_by_title('First Post')


Domino makes it easy to model your forms for testing with Domino::Form. To create a basic form, simply inherit from Domino::Form and define a selector, a key (optional), and a set of fields.

module Dom
  class PersonForm < Domino::Form
    selector 'form.person'

    # For forms with names like `person[age]`, no need to define the
    # locator on each field. Define a key to automatically generate
    # locators based on the field name.
    key 'person'

    # Define a custom selector to click to submit the form
    submit_with "input[type='submit']" # this is the default

    # locate field by label
    field :first_name, 'First Name'

    # locate field by automatically generated name (uses key, person[last_name])
    field :last_name

    # locate field by fully qualified name
    field :biography, 'person[bio]'

    # locate select field by label, acts as select
    # callback mapper operates on selected option nodes
    field :favorite_color, 'Favorite Color', as: :select, &:text

    # automatically handles select[multiple]
    # callback mapper operates on selected option nodes: &:value by default
    field :allergies, as: :select

    # locate by id, convert value via callback
    field :age, 'person_age', &:to_i

    # use a custom field type for unusual or composite fields
    field :vehicles, '.input.vehicles', as: CheckBoxesField

    # locate a field with a name that doesn't use the key
    field :is_human, 'is_human', as: :boolean

    # still supports attributes for non-input nodes
    attribute :action, "&[action]"
    attribute :submit_method, "&[method]"

In the above example, you can define a field to get a reader and writer method for the field. A form will also provide a mass-assignment writer and a save method to submit the form.

person = Dom::PersonForm.find!
person.age            #=> 25
person.vehicles       #=> ["Car", "Bike"]
person.is_human       #=> true
person.favorite_color #=> Blue

person.age = 35
person.age #=> 35

person.set(vehicles: ["Car", "Van"], first_name: "Jessica", last_name: "Jones")
person.attributes #=> { first_name: "Jessica", last_name: "Jones", biography: "", favorite_color: "Blue", age: 35, vehicles: ["Car", "Van"], is_human: true }

Domino::Form provides basic field types for text inputs and textareas, single-selects, and boolean fields. You can create custom field types for more complex form inputs by subclassing Domino::Form::Field and overriding the read and write methods. For example, if you have a collection of check boxes, this might suit your needs:

class CheckBoxesField < Domino::Form::Field
  def read(node)

  def write(node, value)
    value = Array(value)
    node.find(locator).all('input[type=checkbox]').each do |box|

Provide your custom class using the :as option when defining your field, as shown in the example above.

Accessing the Attribute/Field Node

The named accessor method for any field or attribute will yield the Capybara node of the attribute if you pass a block. You can use this to check certain properties of the node without having to break out of your Dominos.

Example: Checking available options in a select field

person = Dom::PersonForm.find!
expected_options = ["- Select a Color -", "Red", "Blue", "Green"]
assert_equal expected_options, person.favorite_color { |n| n.all('option').map(&:text) }

Example: Checking the tag of the node containing the attribute value

person = Dom::Person.find_by!(uuid: "e94bb2d3-71d2-4efb-abd4-ebc0cb58d19f")
assert_equal "h2", { |n| n.tag_name }

Integration with capybara

Domino uses capybara internally to search html for nodes and attributes. If you need to do something special, you can have direct access to the capybara node.

module Dom
  class Account < Domino
    selector "#accounts li"
    # Returns this node text
    def text

For more information about using Capybara nodes, check Capybara Documentation.

Dealing with Asynchronous Behavior

When working with Capybara drivers that support JavaScript, it may be necessary to wait for elements to appear. Note that the following code simply collects all Account dominos currently on the page and returns the first:

Dom::Account.first # returns nil if account is displayed asynchronously

When you are waiting for a unique domino to appear, you can instead use the find! method:

Dom::Account.find! # waits for matching element to appear

If no matching element appears, Capybara will raise an error telling you about the expected selector. Depending on the Capybara.match option, this will also raise an error if the selector matches multiple nodes.

Integration with Cucumber

Add a features/support/dominos.rb file, in which you define your dominos.

Use them in your steps.

Integration with Test::Unit

Include "domino" in your Gemfile if using bundler, or simply

require 'domino'

If you're not using Bundler.

Now, define your Dominos anywhere you want. The easiest place to start is in your test_helper.rb (doesn't have to be inside a Rails test class).


Check out Domino Example for an example of using Test::Unit and Cucumber with Domino.


Copyright (c) 2011 Nick Gauthier, released under the MIT license