Rails NameError : uninitialized constant RelationshipsController

I am trying to run a test of my app buy my relationships_controller_spec.rb file won't run. Here's the error I get:

Exception encountered: #<NameError: uninitialized constant

Here's the code for my relationships_controller_spec.rb file:

require 'spec_helper'

describe RelationshipsController do

  describe "access control" do

    it "should require signin for create" do       post :create       response.should redirect_to(signin_path)     end

    it "should require signin for destroy" do       delete :destroy, :id => 1       response.should redirect_to(signin_path)     end   end

  describe "POST 'create'" do

    before(:each) do       @user = test_sign_in(Factory(:user))       @followed = Factory(:user, :email => Factory.next(:email))     end

    it "should create a relationship" do       lambda do         post :create, :relationship => { :followed_id => @followed }         response.should be_redirect       end.should change(Relationship, :count).by(1)     end

    it "should create a relationship using Ajax" do       lamda do         xhr :post, :create, :relationship => { :followed_id => @followed }         response.should be_success       end.should change(Relationship, :count).by(1)     end   end

  describe "DELETE 'destroy'" do

    before(:each) do       @user = test_sign_in(Factory(:user))       @followed = Factory(:user, :email => Factory.next(:email))       @user.follow!(@followed)       @relationship = @user.relationships.find_by_followed_id(@followed)     end

    it "should destroy a relationship" do       lambda do         delete :destroy, :id => @relationship         response.should be_redirect       end.should change(Relationship, :count).by(-1)     end

    it "should destroy a relationship using Ajax" do       lambda do         xhr :delete, :destroy, :id => @relationship         response.should be_success       end.should change(Relationship, :count).by(-1)     end   end end