Method help

debate.rb

# models/debate.rb
class Debate < ActiveRecord::Base
  attr_accessible :opposition_id, :proposition_id, :title

  validates :proposition_user_id, presence: true
  validates :proposition_id,      presence: true
  validates :title,               presence: true

  has_many :users
  has_one :proposition
  has_one :opposition

end

debate_spec.rb

require 'spec_helper'

describe Debate do

  #let(:prop_user) { FactoryGirl.create(:user) }
  #let(:opp_user) { FactoryGirl.create(:user) }
  before do
    @prop_user = User.new(name: "Prop User", email: "[email protected]")
    @opp_user = User.new(name: "Opp User", email: "[email protected]")
    @debate = Debate.new(title: "Test Debate")
    @prop_argument = @prop_user.proposition.build(title: "Prop Title")
    @opp_argument = @opp_user.opposition.build(title: "Opp Title")
  end
  subject { @debate }

  it { should respond_to(:title) }
  it { should respond_to(:proposition_id) }
  it { should respond_to(:opposition_id) }

  describe "when the debate has no title" do
    before { @debate.title = " " }
    it { should_not be_valid }
  end

  describe "when the debate has no prop id" do
    before { @debate.proposition_id = nil }
    it { should_not be_valid }
  end

  describe "when the debate has no opp id" do
    before { @debate.opposition_id = nil }
    it { should_not be_valid }
  end
end

proposition.rb

# models/proposition.rb
class Proposition < ActiveRecord::Base
  attr_accessible :footnotes, :response, :slide, :title

  belongs_to :user
end

user.rb

# User model as requested.
# models/user.rb -->

class User < ActiveRecord::Base
  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i

  attr_accessible :email, :name, :password, :password_confirmation
  has_secure_password

  has_many :propositions
  has_many :oppositions

  before_save { |user| user.email = email.downcase }

  validates :email, presence:   true,
                    format:     { with: VALID_EMAIL_REGEX },
                    uniqueness: { case_sensitive: false }
  validates :name, presence: true, length: { maximum: 49 }
  validates :password, presence: true, length: { minimum: 6 }
  validates :password_confirmation, presence: true

end

thanks