Spec out the basic functionality of Event

Remove the no longer needed functionality of Event and add specs that
define the still needed parts.

app/models/event.rb

@@ -5,24 +5,6 @@ class Event < ActiveRecord::Base
   validates :description, presence: true
   validates :agreement, acceptance: true
 
-  belongs_to :track
-  has_one :conference, through: :track
-  belongs_to :user # XXX: Transition to candidate_speaker
-  belongs_to :candidate_speaker, class_name: 'User', foreign_key: 'user_id'
-  has_and_belongs_to_many :speakers, class_name: 'SpeakerProfile'
-
-  enum state: [:undecided, :approved, :rejected, :backup]
-
-  scope :confirmed, -> { where.not confirmed_at: nil }
-
-  # XXX: this belongs in a decorator
-  STATE_TO_GLYPH = {undecided: 'question-sign', rejected: 'remove', approved: 'ok', backup: 'retweet'}
-  STATE_TO_CLASS = {undecided: 'warning', rejected: 'danger', approved: 'success', backup: 'info'}
-
-  def confirmed?
-    !!confirmed_at
-  end
-
   private
 
   def self.inheritance_column

spec/models/event_spec.rb

@@ -0,0 +1,42 @@
+require 'rails_helper'
+
+describe Event, type: :model do
+  let(:event) { build :event }
+
+  it 'is invalid if the event agrement is not accepted' do
+    event.agreement = false
+    expect(event).to have_error_on :agreement
+  end
+
+  it 'is invalid without a title' do
+    event.title = ''
+    expect(event).to have_error_on :title
+  end
+
+  describe 'length' do
+    it 'must be present' do
+      event.length = ''
+      expect(event).to have_error_on :length
+    end
+
+    it 'must be a number' do
+      event.length = 'foo'
+      expect(event).to have_error_on :length
+    end
+
+    it 'must be larger than zero' do
+      event.length = '-10'
+      expect(event).to have_error_on :length
+    end
+  end
+
+  it 'is invalid without an abstract' do
+    event.abstract = ''
+    expect(event).to have_error_on :abstract
+  end
+
+  it 'is invalid without a description' do
+    event.description = ''
+    expect(event).to have_error_on :description
+  end
+end