Glimmer's Got BDD through RSpec and SWTBot

I got an RSpec Story Runner (Cucumber) test passing with Glimmer code that tests whether a user logs in successfully.

RSpec is a Ruby library that encourages BDD (Behavior Driven Development,) enabling you to drive the functionality of your application from the outside in by specifying the external behavior from the user's point of view and in the user's language.

Here is the test I got passing with Glimmer:

Feature: Login feature
  In order to keep user data secure
  As a user
  I would like to be authenticated before I can access my data
  
  Scenario: Login
    Given I fill in "User" for "Username"
    And I fill in "Pass" for "Password"
    When I "Login"
    Then my status should become "Logged In"

It uses SWTBot behind the scenes to execute the scenario steps, such as filling in text fields and pressing the login button.

Here is the user-interface:



Here is the user-interface Glimmer code relying on data-binding:

    @shell = shell {
      text "Login"
      composite { 
        layout GridLayout.new(2, false) #two columns with differing widths
        
        label { text "Username:" } # goes in column 1
        text {                     # goes in column 2
          text bind(presenter, :user_name) 
          enabled bind(presenter, :logged_out)
        } 
        
        label { text "Password:" } 
        text(SWT::PASSWORD | SWT::BORDER) { 
          text bind(presenter, :password) 
          enabled bind(presenter, :logged_out)
        }
        
        label { text "Status:" } 
        label { text bind(presenter, :status) }
        
        button { 
          text "Login"
          enabled bind(presenter, :logged_out)
          on_widget_selected { presenter.login }
        }
        
        button { 
          text "Logout"
          enabled bind(presenter, :logged_in)
          on_widget_selected { presenter.logout }
        }
      }
    }
    @shell.open

In a future post, I will discuss the technical details of how this works.