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Project: Dill

End-to-end testing

Dill lets you interact with page elements via widgets. We initially intended them to be an implementation of the Page Object pattern, which typically means that you interact with each widget solely through its custom-defined API.

So you would, for example, define the following widget:

(Don't worry if you don't understand all of the details. We'll explain them later.)

class Plants < Dill::Widget
  root '#plants'

  widget :water, 'button.water-plants'

  def water
    click :water
  end
end

and then use it like this:

widget(:plants).water

This is acceptable. If you change the way how you water the plants (for example, let's say you now need to confirm that you really want to water the plants) then you only need to change #water's implementation, and everything works.

The role-based approach

Even though the above approach works, it has a couple of drawbacks:

First, it hides UI interaction under another fragmented layer of indirection (not counting the one Dill already provides). If you need to interact with multiple widgets, you need to keep shifting contexts to understand, for example, what it means to call #water on widget(:plants).

Second, a meaningful business action (say, "signing in") often involves interacting with more than one widget, forcing custom widget API's like #water to do little more than wrap, for example, a single click. Since it's in our best interest to uphold a Single Source of Truth, we'll want define what "signing in" means in a single place.

We settled on using widgets as a translation layer between the UI and the code, instead of letting them encapsulate meaningful business knowledge. That business knowledge is now handled by roles.

So, you would define the following role, instead:

class Gardener < Dill::Role
  widget :water_plants, 'button.water-plants'

  def water_plants
    visit plants_path

    click :water_plants
  end
end

and then use it like this:

gardener = Gardener.new

gardener.water_plants

Last published almost 7 years ago by David Leal.