User Notification Service Specs

Problem/Feature Description

A SaaS platform sends users notifications when important events occur: account suspension warnings, password change confirmations, and billing failures. The backend team recently completed Notifications::UserNotifier, a service object that dispatches different notification types via email. A code review flagged that this service has no test coverage, and the PR cannot be merged until specs are in place.

You have been asked to write a comprehensive RSpec spec file for Notifications::UserNotifier. The service lives at app/services/notifications/user_notifier.rb. Your spec file should be organized to reflect the structure of the service and provide clear, readable examples that any team member can understand at a glance.

Note: This project does NOT use test-prof or any performance-enhancing spec helpers beyond standard RSpec.

Input Files

The following file is provided. Extract it before beginning.

=============== FILE: app/services/notifications/user_notifier.rb ===============

frozen_string_literal: true

module Notifications class UserNotifier VALID_EVENTS = %w[suspension_warning password_changed billing_failure].freeze DEFAULT_SENDER = 'noreply@example.com'.freeze

def self.call(user_id:, event_type:)
  new(user_id: user_id, event_type: event_type).call
end

def initialize(user_id:, event_type:)
  @user_id = user_id
  @event_type = event_type
end

def call
  return { success: false, response: { error: 'Invalid event type' } } unless VALID_EVENTS.include?(@event_type)
  return { success: false, response: { error: 'User not found' } } if @user_id.nil?

  # TODO: load user from database and dispatch email
  { success: true, response: { delivered: true, event: @event_type } }
end

private

def valid_event?
  VALID_EVENTS.include?(@event_type)
end

end end

Output Specification

Produce a single spec file for the service. The spec should cover:

• Successful notification dispatch for a valid event type
• Failure when the event type is not one of the recognised values
• Failure when user_id is nil

The spec file should be placed at the mirrored path under spec/ and follow standard RSpec conventions for structure and test data setup.