title: Test for destroying associated records when object is destroyed failing in rails app
body: <p>Im stuck on the test in listing 10.15 of Michael Hartls ruby on rails tutorial (<a href="http://ruby.railstutorial.org/chapters/user-microposts#code-micropost_dependency_test" rel="noreferrer">http://ruby.railstutorial.org/chapters/user-microposts#code-micropost_dependency_test</a>). My user_spec.rb is as follows</p>
  
  <pre><code>require 'spec_helper'
  
  describe User do
    before { @user = User.new(name: "Example User", email: "user@example.com",password: "foobar", password_confirmation: "foobar") }
  
    subject { @user }
  
    it { should respond_to(:name) }
    it { should respond_to(:email) }
    it { should respond_to(:password_digest) }
    it { should respond_to(:password) }
    it { should respond_to(:password_confirmation) }
    it { should respond_to(:remember_token) }
    it { should respond_to(:admin) }
    it { should respond_to(:authenticate) }
    it { should respond_to(:microposts) }
  
    it { should be_valid }
    it { should_not be_admin }
  
    describe "with admin attribute set to 'true'" do
      before do
        @user.save!
        @user.toggle!(:admin)
      end
  
      it { should be_admin }
    end
  
    describe "when name is not present" do
      before { @user.name = " " }
      it { should_not be_valid }
    end
  
    describe "when email is not present" do
      before { @user.email = " " }
      it { should_not be_valid }
    end
  
    describe "when name is too long" do
      before { @user.name = "a" * 51 }
      it { should_not be_valid }
    end
  
    describe "when email format is invalid" do
      it "should be invalid" do
        addresses = %w[user@foo,com user_at_foo.org example.user@foo. foo@bar_baz.com foo@bar+baz.com]
        addresses.each do |invalid_address|
          @user.email = invalid_address
          @user.should_not be_valid
        end
      end
    end
  
    describe "when email format is valid" do
      it "should be valid" do
        addresses = %w[user@foo.COM A_US-ER@f.b.org first.lst@foo.jp a+b@baz.cn]
        addresses.each do |valid_address|
          @user.email = valid_address
          @user.should be_valid
        end
      end
    end
  
    describe "when email address is already taken" do
      before do
        user_with_same_email = @user.dup
        user_with_same_email.email = @user.email.upcase
        user_with_same_email.save
      end
  
      it { should_not be_valid }
    end
  
    describe "when password is not present" do
      before { @user.password = @user.password_confirmation = " "}
      it { should_not be_valid }
    end
  
    describe "when password doesn't match confirmation" do
      before { @user.password_confirmation = "mismatch" }
      it { should_not be_valid }
    end
  
    describe "when password confirmation is nil" do
      before { @user.password_confirmation = nil }
      it { should_not be_valid }
    end
  
    describe "return value of authenticate method" do
      before { @user.save }
      let(:found_user) { User.find_by_email(@user.email) }
  
      describe "with valid password" do
        it { should == found_user.authenticate(@user.password) }
      end
  
      describe "with invalid password" do
        let(:user_for_invalid_password) { found_user.authenticate("invalid") }
        it { should_not == user_for_invalid_password }
        specify { user_for_invalid_password.should be_false }
      end
    end
  
    describe "with a password that's too short" do
      before { @user.password = @user.password_confirmation = "a" * 5 }
      it { should be_invalid }
    end
  
    describe "remember token" do
      before { @user.save }
      its(:remember_token) { should_not be_blank }
    end
  
    describe "micropost associations" do
      before { @user.save }
      let!(:older_micropost) do
        FactoryGirl.create(:micropost, user:@user, created_at: 1.day.ago)
      end
      let!(:newer_micropost) do
        FactoryGirl.create(:micropost, user:@user, created_at: 1.hour.ago)
      end
  
      it "should have the right microposts in the right order" do
        @user.microposts.should == [newer_micropost, older_micropost]
      end
  
      it "should destroy the associated microposts" do
        microposts = @user.microposts.dup
        @user.destroy
        microposts.should_not be_empty
        microposts.each do |micropost|
          Micropost.find_by_id(micropost.id).should be_nil
        end
      end
    end
  
  end
  </code></pre>
  
  <p>When i run the tests i get the following error :</p>
  
  <pre><code>  1) User micropost associations should destroy the associated microposts
       Failure/Error: Micropost.find_by_id(micropost.id).should be_nil
         expected: nil
              got: #&lt;Micropost id: 2, content: "Lorem ipsum", user_id: nil, created_at: "2012-12-19 09:49:24", updated_at: "2012-12-19 10:49:24"&gt;
       # ./spec/models/user_spec.rb:133:in `block (4 levels) in &lt;top (required)&gt;'
       # ./spec/models/user_spec.rb:132:in `each'
       # ./spec/models/user_spec.rb:132:in `block (3 levels) in &lt;top (required)&gt;'
  </code></pre>
  
  <p>In my user.rb i have added the dependent :destroy as follows, which is required for the test to pass.</p>
  
  <pre><code>has_many :microposts, dependent: :destroy
  </code></pre>
  
  <p>Why is the test still failing ?</p>
  
  <p>Thank You</p>