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Project: Rspec-fire-roles

Publisher: Chris Vincent

Using roles with rspec-fire

In order to mock roles rather than objects and build more flexible systems
As an avid RSpec user
I want to see failing specs when role interfaces are not honored

Background
Given
a file named "spec_helper.rb" with: 
require "rubygems"
require "bundler/setup"
Bundler.setup

require "rspec/fire"
require "rspec/fire/roles"

RSpec.configure do |config|
  config.include RSpec::Fire
  config.include RSpec::Fire::Roles
end
And
a file named "batch_sender_spec.rb" with: 
require "spec_helper"
require "batch_sender"
require "notifier"

describe BatchSender do
  describe "#send_messages" do
    it "passes each message to the injected notifier" do
      notifier = fire_double("Roles::Notifier")
      instance = BatchSender.new(notifier)
      notifier.should_receive(:notify).with("Subject 1", "Body 1").once
      notifier.should_receive(:notify).with("Subject 2").once

      instance.send_messages([["Subject 1", "Body 1"], ["Subject 2"]])
    end
  end
end
And
a file named "batch_sender.rb" with: 
class BatchSender
  def initialize(notifier)
    @notifier = notifier
  end

  def send_messages(messages)
    messages.each { |msg| @notifier.notify(*msg.compact) }
  end
end
And
a file named "notifier.rb" with: 
module Roles
  class Notifier
    def notify(subject, body = nil); end
  end
end
And
a file named "email_notifier_spec.rb" with: 
require "spec_helper"
require "email_notifier"
require "notifier"

describe EmailNotifier do
  implements_role "Roles::Notifier"
end
Scenarios
  1. A role with a matching implementation
  2. A role with a method with the wrong arguments defined
  3. A role with an implementation missing a method
  4. A role with an implementation with incorrectly-named arguments
A role with a matching implementation
Given
a file named "email_notifier.rb" with: 
class EmailNotifier
  def notify(subject, body = nil); end
end
When
I run rspec batch_sender_spec.rb email_notifier_spec.rb
Then
it should pass
A role with a method with the wrong arguments defined
Given
a file named "email_notifier.rb" with: 
class EmailNotifier
  def notify(message); end
end
When
I run rspec batch_sender_spec.rb
Then
it should pass
When
I run rspec email_notifier_spec.rb
Then
it should fail with "Incomplete implementation of Roles::Notifier. Parameters for #notify(subject, body = nil) do not match."
A role with an implementation missing a method
Given
a file named "email_notifier.rb" with: 
class EmailNotifier
end
When
I run rspec batch_sender_spec.rb
Then
it should pass
When
I run rspec email_notifier_spec.rb
Then
it should fail with "Incomplete implementation of Roles::Notifier. #notify(subject, body = nil) is not defined."
A role with an implementation with incorrectly-named arguments
Given
a file named "email_notifier.rb" with: 
class EmailNotifier
  def notify(name, content = nil); end
end
When
I run rspec batch_sender_spec.rb email_notifier_spec.rb
Then
it should fail with "Incomplete implementation of Roles::Notifier. Parameters for #notify(subject, body = nil) do not match."

Last published about 6 years ago by Chris Vincent.